I tried this recipe and it is wonderful! Even Father liked it, which is saying something.
The only changes I made: I used vanilla whey protein powder instead of unflavored (because that’s what I had), and I added a packet of Equal sweetener instead of concentrated stevia powder (because I can’t tolerate the taste of stevia).
It is definitely not too sweet, more like a mildly sweet peanut butter cup without chocolate than actual fudge. Actually, drizzling the top with melted sugar-free chocolate would be pretty good, come to think of it.