Betty Crocker. From the 1950's ot ’60’s. Totally T&T. Classic. If you don't have it, I can dig it out later. Oh, here it is from the Cooky Book: https://www.onsuttonplace.com/old-fashioned-oatmeal-raisin-cookies/

So, it says drop, but I'm pretty sure we sort of flattened the glob with the back of the spoon—quenelle style, not scoop. We did that with chocolate chip cookies too. I didn't read the blog. Just scrolled to the recipe, which looks right. ”Shortening” in this case means any. We use baking sticks (100 C per Tbsp), but butter, Crisco (adjusted), or even lard, should all work, with slightly different textures. Regular Quaker oats. Cane sugar. Gold Medal AP. Fresh Sunmaid raisins, plump from the box, not boiled. I last made them about 20 years ago, but just as good as when I was a child. I'm sure they can be made with modern ingredients, but I've given you the classics for comparison.

The Silver Palate oatmeal cookies are my go-to's. The best thin, chewy oatmeal cookies in the world. Prolly cos they're made with a whole cup of butter :-) I use Quaker Oats and sometimes sub craisins for the raisins.

https://www.silverpalate.com/recipe/temptations/silver-palate-oatmeal-raisin-cookies

^I haven’t tried the Silver Palate recipe but that’s a darn good resource.

I do love Quaker’s “Vanishing“ recipe (also a cup of butter for the version I use). I normally chill the dough for at least overnight before baking. However, I sometimes make the cookies for ice cream sandwiches. In that case I don’t chill the dough, and the cookies are flatter.

Oatmeal Scotchies - follow this link

Oatmeal Cranberry Cookies - follow this link - substitute raisins for cranberries if you desire.

T&T?

Tried & True. May be an old Garden Web abbreviation.

Thanks, bbstx If I'd read the OP more thoroughly I'd have seen it there.

I'm not sure it's so easy to make soft oatmeal cookies that are also thin. When I make oatmeal cookies and flatten them before baking so they're thin, they get very crispy, which is what I prefer. All I can think of is underbaking, which would likely mean some trial and error. I use a 1.5" inch cookie scoop.

Oatmeal Cookies 2-2 1/2 doz.

1/2 cup shortening (5 Tbs butter/ 3 Tbs oil)

1 cup sugar

1/4 tsp. salt

1 egg

1/2 tsp. baking soda

1 cup flour

1 1/4 cups rolled oats

cinnamon

nutmeg

1/3-1/2 cup walnuts

1/3 - 1/2 cup raisins

Oven 350F

Cream shortening with sugar, add egg and beat until light & fluffy.

Beat in spices and salt.

Stir in flour and soda until completely mixed, then add oats, raisins and walnuts and mix well.

Drop Tbs 2 inches apart on parchment lined baking sheet, flatten with a fork.

Bake 10-12 minutes, until lightly browned. Cookies will crisp up as they cool.

I normally think thin=crisp. Generally, the more butter and warmer the dough the more they spread and hence the thinner.

Agree with mtndredux regarding butter and warmer dough. Mine will bake up thinner and can be crispier. However, less baking time can still result in soft.

Yes, darn I meant to add that. Cook one or two at a time and experiment with timing to get the texture you want. Make sure to let it cool on a wire rack before your judge texture.

Also, from Sally's Baking Addiction: Using more brown sugar than white sugar results in a moister, softer cookie. An extra egg yolk increases chewiness.

Something from a lecture by a food scientist: a teaspoon of water in a batch makes for chewy cookies.

By ”thin” I thought you meant not-mounded. The BC recipe, flattened somewhat after dropping, gives a flat but not thin-thin cookie. Thick as raisins. For thin-thin, bendy-soft, with the raisins sticking up, use butter—more than usual—so they really melt and spread, as Mtnrdredux said, and slightly underbake, as Carol said. Pull them just when the edges are thinking anout getting brown, but not yet there and put the baking sheet on a wire cooling rack until merely warm, and the cookies are set enough to lift with a pancake turner without squishing. Put cookies on a wire tack to finish cooling and steaming out. This works with most standard, moist cookies, but not drier ones like shortbread.

I like to use all butter, although I'm aware of the results of using part shortening. It's just not my choice. Sally's baking addiction is a very reliable source and one I would trust.

I seem to recall that quite a while ago, there was a recipe for these kinds of cookies on the website at either America Test Kitchen or Cook’s County.

Smiles,

Sooz

The Great American Cookies Company, made a pizza size chocolate chip soft cookie. Years before now, there was a recipe that made a soft cookie. It used Karo syrup instead of granulated sugar. Try that istead of some of the regular sugar.