You're basically talking about moisture control, which is one of the key differences between good cooking and bad cooking. You can't substitute home canned runny tomatoes for ketchup. They're not analogous products and only have tomatoes in common. You can put your tomatoes in a small pan and reduce the heck out of them until they're a paste, but that could really alter the flavor. Or you can drain them and either reduce the juice or the solids, which might work better. Or you might get away with just pureeing some of the most solid parts of some drained tomatoes then draining them again.

You can also drain the sour cream. The way the recipe reads, it sounds like you need the whole cup of sour cream, but you could drain some yoghurt in cheesecloth until it's the consistency of sour cream.

Fresh mushrooms have a lot of water in them. It's important to give them a rest, covered on low heat, at least 8-10 minutes if sliced, and maybe more if whole, to get the water out. Or you could start with dried and rehydrate them, maybe in the juice from the tomatoes, but they still need to have the liquid reduced when you cook them.

You also need to account for the acid in combining the tomatoes with dairy, lest you get curdle.

The white sauce is the easiest thing. Just use enough flour or starch, and heat long enough to reduce, to get the globby consistency of condensed soup. Maybe use evaporated milk or fresh cream. IME, making too much is easier than extending. You can use oil as a base instead of butter, but butter will thicken up better.

If I were you, I wouldn't do all these things at once. Since the salt is the main problem you mentioned, I'd start with the white sauce, and try the rest of it as is. After you've sautéed the mushrooms dry, combine them with the white sauce and let them marry and come to the right consistency, then make the dish as usual for the rest.

Good luck!

I would suggest instead of adding mushrooms to a white sauce, that you make a mushroom soup with the mushrooms.

Saute 8 oz of fresh mushrooms with your onions and garlic. Once your mushrooms are past rendering out and have started to go au sec, sprinkle in a tablespoon or so of flour, and stir in to make sure everything is well coated. Cook for a minute or few to cook the raw flour flavor out. Then add in a cup or so of your liquid- milk, cream, broth/stock- slowly, whisking it in to keep it smooth.

You should have a fairly stiff "soup" once you are done, somewhere around the consistency of the canned soup. Adjust liquid as needed.

Allow to cool a bit before adding in your other stuff. Since you are starting with the "wet" veggies and doing the saute to au sec before creating the "soup", how liquid or stiff your final product will be is easier to control than adding mushrooms to a white sauce. The flavor marries and carries through better too.

Drain your tomatoes well, before adding in. Reserve liquid to add in if needed.

A cup of sour cream sounds excessive to some, but hey I'm from dairyland so sounds right to me, lol. Start with a half cup and see if you like the consistency or not. If too thick, add some of the reserved tomato juice. If not creamy enough, add some more sour cream. You can adjust a bit by adding cream cheese, or you can use drained greek yogurt. I bet a nice fresh creamy ricotta could work too.

I would sub tomato paste for the ketchup.

I would sauté the mushrooms, then remove from pan and set aside. Now sauté the onions in butter, then add the garlic and give it another minute. Then I’d add a heapin tablespoon of the tomato paste and some herbs- thyme, marjoram, paprika. Over this I would sprinkle 2 T of flour and mash it in to get rid of the raw flour taste. Now slowly stir in a can of evaporated milk. Slowly so it doesn’t get lumpy. Adjust the seasonings, if you are good, add the cooked mushrooms and cooked shrimp. I would only add the sour cream if you want it

sautee a couple tablespoons of onion in 2 T butter, when they are soft....add 2T flour....stir and slowly add 1 cup LOW SODIUM chicken broth and stir....simmer 5 minutes and shut off. In another pan or same pan which you have washed after storing the onion mix....saute a cup of sliced fresh mushrooms in 2 T butter....slowly....and continue cooking until the water has boiled mostly off....add 2T flour stir and add 1 cup milk or half and half...cook stirring constantly for 5 minute and add the first mixture to it.....add 1 T tomato paste stir and bring to hot temperature but do not boil.Add juice of half a lemon and Add cajun seasonings and garlic powder to taste and as much shrimp as you want....
I would add a little dry sherry too....serve over white rice.

I would do as localeater suggests but use half and half or whole milk instead or a little heavy cream. I also think some home canned tomatoes would be fine, add a little texture.

Cooking the shrimp in the mixture though would give it more shrimp flavor

You know you can also find low sodium versions of all the prepared items. Have you thought of trying that?

I would probably sub fresh sauteed mushrooms for canned anyway, tho.

I made the dish tonight. Sauteed the garlic, onion and mushrooms in 3 TBLSP butter and then added the shrimp. That all gave up a bit of water. Tried thickening it with a mix of sour cream and tomato paste. Meanwhile made a thick white sauce with 3 more TBLSP butter and 3 TBLSP flour. Used lowfat milk and lowfat sour cream, which is why I didn't mind using a lot of butter. Everything unsalted. Also added a tsp cajun seasoning. Was kind of bland so added some healthy dashes of worcestershire sauce. Added a couple more TBLSP tomato paste to get the right consistency. Would have benefited from a dash of sherry or wine. Was kind of rich and still a tad bland. I had to add more shrimp as it was originally a lot of sauce and not much stuff in it. Hubs liked it.

Next time maybe Thai red curry paste instead of tomato paste, and maybe coconut milk. Different dish but more to my flavor profile likings. But I'll bet my plain Jane Dad liked the original, as does my husband.

Looking through the original community recipe booklet, circa 1961, it seem the solution to every fancy dish was a can of cream of something soup and a cup of sour cream, and some ketchup if it needed a little zing . . .

Edited to add that the whole thing gave me indigestion. Too rich, too much dairy, even though I used lactose free milk . . .

This is a very strange recipe to me. I don't think I've ever had shrimp with mushrooms, and I know I've never had shrimp in a white sauce, although I am okay with that - if it does not have tomato in it. I also would never add sour cream to shrimp, as shrimp is rich enough.

Normally I make Shrimp Creole instead, which is just shrimp with tomato, onion, garlic, and celery with Cajun seasoning, served over rice. I often add okra to this, but you could add filé power instead - I just happen to love okra. Then it becomes more like gumbo, however.

If I were making a mushroom sauce, I might add clams or crab, but I don't think I would add tomatoes. It is a bit like the difference between New England clam chowder (which I actually prefer) to Manhattan style, which is okay, but not my favorite. It is either white or red but not both.

Anyway, I think there are better uses for shrimp, and in general, the simpler shrimp recipes tend to be better IMO. I want to taste shrimp - not disguise it.

Long Island clam chowder- it's a variant that has cream and tomato- like New England and Manhattan had a chowder baby.

they make no salt added canned mushrooms

and low salt mushroom soup. you can also

buy low salt ketchup

here is a 1922 version of recipe

from: The Huntington PressHuntington, Indiana
17 Dec 1922, Sun • Page 3

with no canned ingredients

Shrimps,New Orleans Style. - Two tablespoons butter, 1 cup of canned shrimp,
1 cup hot boiled rice, 4 cup heavy cream, teaspoon salt, teaspoon
celery sail, few drops onion juice, cup tomato sauce Melt butter, add
shrimps and three minute. Add cream, rice, and seasonings. Heat and
serve garnished points of hot buttered toast. Time in combining, 10
minute Time - in cooking, 8 minutes. Recipe makes four servings.

I love shrimp creole and like to add a splash of cream at the end not much but just enough to make it opaque and not translucent.

My mother when I was young would use canned shrimp occasionally in a number of things and it's a very nostalgic food that I don't eat these days.

That's how I envisioned it, sort of a creamy version of shrimp creole . . . I think it would be much better to make a tomato sauce and add just a splash of cream to it. I often do that with Italian style tomato sauce when serving over pasta. The original recipe that my Mom posted was way too rich, but like I said, all the entrees in that community cookbook were very similar, can of cream of something soup and then add sour cream . . . My Dad likes that kind of bland, fatty salty food, the epitome of "fancy" in his mind since I'll bet growing up in the Depression and during WWII, butter and other rich dairy were big treats . . .

lpink, here is an excellent substitute for cream of mushroom soup. It is Mushroom Bechamel Sauce from Robert St John. I’ve made it before and it is fabulous. I froze it in 1 cup portions. It will separate a bit when thawed, but you can stir it back into shape! You can control the amount of salt easily. I’m going to post the recipe below, but I would urge you to go to his site and read the whole blog post. It is hilarious!

MUSHROOM BÉCHAMEL SAUCE

(should be used as a legit substitute for canned cream of mushroom soup)

1 Tbl Olive oil, light

1 /2 cup Onion, minced

1 /4 cup Shallot, minced

1 /4 cup Celery, minced

2 tsp Salt

1 tsp Garlic, granulated

1 /2 tsp Thyme, dry

10 oz Mushrooms, cleaned, sliced (4 cups)

3 cups Chicken broth, warm

1 /2 cup Butter

3 /4 cup Flour

1 cup Whipping cream

Heat oil in a three-quart saucepot over low heat. Add onions, shallots, celery, and salt. Cook vegetables until tender. Add mushrooms and increase heat to medium. Cook 10 minutes, stirring often. Add chicken broth, garlic and thyme. Bring back to a simmer and cook 10 more minutes.

In a separate skillet, make a light-blonde roux by melting butter and stirring in flour. Add to simmering broth mixture. Cook three to four minutes and add cream. Freezes well.

Yield: two quarts

Thanks Bbstx. I actually have all the ingredients except the shallots but I think I can sub some chives or scallions, thinking about making it this weekend.

According to Bon Appetit, you can sub chopped onions for shallots 1:1. You need to chop the onions slightly smaller than usual and cook them down a bit more than usual. I hate to admit, I make this substitution quite often. I don’t have enough recipes calling for shallots to keep them on hand.

They are quite expensive and I don't use them often enough to dole out the money. Seems like onions give a very similar flavor for the dollar.

Well, I ended up making another old school recipe out of the community cookbook, "hamburger stroganoff" also from my mother, although I never remember her making either dish she submitted. Probably a "company" recipe back in the day. Instead of the suggested cream of chicken soup, I did something similar to what Lindac suggested, made a sauce I guess would be called "velouté" from no fat salt free chicken broth (plenty of butter for the roux) and then flavored with sauteed mushrooms and onion, and a few other seasonings, then made it creamy with lite sour cream. Had to add some dry white wine to give it more "tang" than the lite sour cream. I guess I could have dusted with parm, but with dill and parsley that was enough. Needed a bit of tamari. I added the hamburger after cooking and draining it. Used 2/3 meat and 1/3 fake meat crumbles. It was good but a bit "stodgy" as they say. Dad of course loved it . . . I was fine but it gave hubs gas . . . sigh, our days of lovin' up on dairy may be limited . . .