and chocolate flavor is strong enough to mask any bitterness that may occur with milder-flavored foods, but texture may be off.

https://www.stevia.org/stevia-recipes/stove-top-cooking-with-stevia/chocolate-fudge

The trick seems to be limiting the amount of fluid. Adding non reconstituted dry milk would do the trick and net you something fudgy instead of something like thick cocoa. It's worth a try, just have your cocoa mugs handy just in case.

Not sure I want to drink warm peanut butter.

for things like fudge is that you end up with fudgy soup.

I didn't see peanut butter as an ingredient in this particular recipe. You might be able to get away with adding it.

if the Stevia would work in it.

(My Memere's peanut butter fudge. We have a family event coming up, and I thought I might surprise my family. Truth is, I do have enough sugar to just stick w/ the original recipe.))

because what I've read says stevia won't work, it doesn't act like sugar at all, it just adds sweetness.

Some recipes are supposed to be bad for you. Fudge is one of them. You might as well stick with the tried and true recipe, lest the family be shocked instead of surprised.

I would guess that if it's classic style, with chocolate (not cocoa), a candy thermometer, and cooking to a specific temperature, etc., that it wouldn't work. Sucrose sugar chemistry is so complex as to be an entire area of study and I'm not sure that substituting even another sugar like dextrose or fructose would behave the same way. (My dad at one point wanted to open a candy store, making all the stuff. It never happened, but I still have all his reference materials. Plus the marble slab.)

But the various other types using cocoa plus powdered sugar, marshmallows or other ingredients to get the texture might allow you to substitute Stevia for some, if not all of the sugar ingredient(s). Maybe all. Why not give it a try?

Heck, give the classic PB fudge a try. Let us know how it turns out. If it's even close enough to show promise, you may be able to come up with an adjustment that works on a second batch.

However, I think it would work for certain things like boiled custard, hot cocoa, or the lemon pudding cake my family loves. It just seems to me that a dish which is very liquid would absorb the stuff.