Fresh and frozen broccoli should be the same weight- a 16 oz bag of frozen is going to have a pound of broccoli, just like a pound of fresh is going to be 16 oz.

How many cups per ounce/pound depends on how small you cut up your broccoli. How much volume the broccoli takes up can vary greatly even though the basic weight stays the same.

If you are using just florets, or opting to include stem can count for something too. Florets take up more volume for weight than stems do.

If you find a recipe you like except for the frozen part- while you are at the store, take frozen bags over to the produce area and compare. If a recipe calls for a 10 oz bag, how is cut up in there- you can get a feel just handling the bag. Look at broccoli and see what looks around the same amount- and also take time to use the scale and see how it weighs up.

And yeppers, you can par-cook your broccoli for a couple minutes before you start making the casserole. Depending on the recipe cooking time, and how you cut up your broccoli, you may need to tinker a bit for how long to par-cook. But I find it's nice to "take the raw off" fresh broccoli.

Louise, I was gifted with this recipe about 50 years ago. It is the only time I cook with Velveeta cheese and that is the cheese that must be used. It is my expected 'go-to' recipe for family holidays and large gatherings. And every time people will ask me why I did not bring a larger sized casserole...that they loved it!

For this recipe any variety of vegetable can be used including just broccoli. However, I chop a combination of the following veggies to fill the size pan used:

Some onion

Zucchini and/or summer squash

Broccoli

Cauliflower

Lightly steam the vegetables and spread in pan.

Make enough thick white sauce with a generous amount of Velveeta cheese added to bind the vegetables. Add 1/4 tsp. each of onion powder and celery salt to each cup of cheese sauce. Pour sauce over vegetable mixture in pan, spreading evenly.

Cover surface of casserole with a generous amount of buttered bread crumbs. Bake at 350 degrees for about 40 minutes or until bread crumbs are browned.

Note: Casserole can be made early in the day and refrigerated. Remove from fridge 1/2 hour to warm before baking. Add buttered bread crumbs just before it goes in the oven.

Velveeta?. Who’d a thunk? That’s awesome, thank you!

There is this recipe on allrecipes.com:

https://www.allrecipes.com/recipe/20516/broccoli-cheese-bake/?internalSource=staff%20pick&referringId=14355&referringContentType=Recipe%20Hub

It does show 8 cups of fresh broccoli steamed to a sauce made with ½ C butter and 1½ C milk. You could switch the cheese or add buttered crumbs to the top.

This is the sauce I use for cheesy casseroles......works with Broccoli, broccoli and cauliflower....assorted mixed vegetables with noodles...you can add cooked chicken and the sauce will freeze....or make half the recipe.

Cheesy sauce

Sautee 1½ cups finely chopped onion in ½ cup butter and ¼ cup olive oil until soft.

Add 1 cup flour
and stir and cook about 30 seconds and add 2 cups of chicken broth slowly and
whisk.

Add 1 tsp
garlic powder, and 3 cups of milk….cook and stir until thick and the “flour
taste” is gone. Add 3 cups shredded chedder cheese and 1 cup of grated parmesan
cheese, about 1 tsp fresh ground pepper and juice of a small lemon. Makes about 9
cups of sauce.

Good with
pasta, chicken, mushrooms and assorted veggies.Quick blanch raw vegetables or use frozen. Will sauce about 3 9 by 10 casseroles.
Cover and heat.

This is one of those things I would eyeball...

Reading this reminded me that I have leftover steamed broccoli that I needed to put away. It was just barely steamed and is still crunchy.

When I make a broccoli casserole, I use steamed fresh broccoli (still crunchy) and add a mushroom/onion velouté sauce to it and bake it - no dairy, although you can add Fontina cheese on top if you need dairy with it. To make the velouté sauce, I use the cooking liquid from the broccoli and add a bit of vegetable soup base (that I buy at a restaurant supply store) instead of salt. Sometimes I use a mushroom soup base instead or I soak dried mushrooms in hot water and use that liquid for both cooking the broccoli and making the sauce. I chop the soaked dried mushrooms and add to the casserole. If I use fresh mushrooms, I sauté them with onions first.