In a recent thread, someone posted a link to Cecil’s column on circus peanuts. This fired up my curiosity a bit, and through casual browsing managed to find this “Circus Peanut Recipe”
The first few ingredients are:
Share your recipes that only a sick mind could have created.
I had a feeling it would be this. 
I ran across this a couple of years ago and couldn’t resist bringing it to our family Thanksgiving. I purposely told no one what was in it until everyone had put it in their mouths. They were properly horrified.
The next year I brought a Cat Litter Cake, complete with litter scoop and stuffed cat.
Now I’m having a hard time finding evil recipes, but it doesn’t matter anymore since no one will touch anything I bring. 
Peruse through any edition of the Betty Crocker cookbook, and you’ll find Satan’s assprints all over it. Hint: Go to the party snacks section. My favorites are slices of balogna spead with peanut butter and impaled decoratively on toothpicks, and walnut halves glued together with Cheez Whiz.
Penn & Teller’s “How to Play with Your Food” gives a recipe for a heart-shaped jello cake that bleeds when cut.
I’ve made cat poop cookies which weren’t all that yummy (though they looked appropriately hideous) but that’s not quite the same sort of “evil” as in the OP. I think “evil” per the OP is more the “ingredients that should be banned” or “should never be combined”…
In the same tone as the cat poop cookies and the litterbox cake (I made that one too, a few years back - it actually tasted good!), one can have one’s boogers served either sweet or savory. Haven’t tried any of these yet… but the Boy Scout Halloween party is just 4 months away :::insert evil cackle:::
A few months ago, my mother in law – who is known for her penchant for trying recipes better left well alone – made a lemon Jell-o salad. With beets. And cabbage. And horseradish.
I ain’t lyin’: by Googling the ingredients (one comes up with many more hits than one would think), I found the recipe online.
It’s seems strange that someone (“Dot,” I suppose) thought, “How can I improve this lemon Jell-o? I know: I’ll add beets.” And then, because that ended up tasting awful, "I’ll make it better by adding cabbage.
“Nope, that somehow made it even worse. How about some horseradish?”
However bad you might think it tasted, you’re not even halfway there.
Paging James Lileks…
I bet you’re wrong. There is no worse form of “bad” to the flavor I’m currently imagining.
Many years ago my mother thought it would be a nifty idea to add peanuts to cole slaw. And she made a huge batch of it. It pretty much tasted like Hitler’s testicles, we all agreed. Did she throw it out? Hell no. We had to eat that crap every night until it was gone. That was one evil month.
I do have to say that ketchup on hot dogs and 20-year-old scotch watered down with tea seem like perfectly acceptable things by comparison.
For some reason people really like to fuck around with fudge:
Velveeta Fudge:
“Surprise” Chocolate Fudge:
http://allrecipes.com/Recipe/Surprise-Chocolate-Fudge/Detail.aspx
In the interest of full disclosure, I have made or eaten neither.
I once made a recipe that involved cooking beef liver in milk with prunes. I was young and figured that if it was a real recipe, it had to be OK. It was not OK. I threw the whole casserole thing out in the apartment dumpster.
Velveeta fudge is great! …Tastes like a really creamy premium fudge.
…and I love those chinese pastriies with sweet bean paste. I love the texture and richness of smushed beans, great mouthfeel. Like velvet for the tongue…I’ll have to give the bean fudge a try!
My MIL, who is normally a very good cook, decided to spring this one on my husband once:
You may not think it’s all that bad, looking at the ingredients. You’d be wrong. Blech. It’s extremely sweet and has a weird off flavor I cannot describe.
Fortunately she got the hint and never made it again.
Any recipe that ends with the direction to add more sugar can’t possibly be good for you.
Really? My friends and I love that stuff. It’s certainly not health food, but it’s damn tasty - every time my friends hold anything resembling a potluck, they request that I bring puppy chow.
shrug To each their own.
No freakin’ way, that’s totally Muddy Buddies. Chex used to have the recipe on the box… and I would pour them into a bowl with milk and eat them like cereal. yummmmmmmmm
Oh yeah, I love that puppy chow stuff. I’d eat it 24/7 if I didn’t care about my waistline and heart.
Here’s my entry. My mom fed this to us when a special occasion arose:
(oops, fucked that up! Here are the evil recipes)
**Bologna Cups**
-Fry thick slices of bologna until they curl up and get brown.
-Fit the curls of “meat” into the cups of a muffin tin.
-Fill each hollow cup with canned creamed corn.
-Make some instant mashed potatoes.
-Top the meaty/corny cups with “potatoes.”
-Bake until the potato stuff crusts up and browns.
-Ease them out of the muffin tin and dig in.
Man, I loved those bologna cups! I recently describe them to my daughter’s SO, and he begged me to whip up a bunch. I just might do it!
Another evil childhood recipe was . . .
**Hot Diggity Dogs**
-Crush up some corn flakes.
-Pull hot dogs out of the package.
-Coat the hot dogs in ketchup, then roll them in the crushed cereal.
-Bake until . . . well, I guess until they look done.
-Dig in! We probably ate them with creamed corn and instant mashed potatoes but I’ve successfully managed to block that detail.
Two jobs ago I was always given much grief for never going with the guys to White Castle’s. I despites “belly-bombers”, having unfortunately eaten some last right before swimming in a 200 IM race, and then getting to deposit them all over the gutter after finishing dead last.
Anyway, someone’s wife was having a pot-luck, and all the guys were sure I’d bring some frou-frou dish that no one else would like. So I found a recipie for “bachelor paté”:
Pop two White Castle cheeseburgers (buns and all) into a food processer and whip until smooth. Add enough white wine to get to the desired consistence (a few tablespoons should do).
I brought it with a nice little platter of crackers and cheeses… it was disgusting: greasy, oniony, meaty. Urgh. Of course the other guys wolfed it right down. The hostess was rightly horrified when I told her what it was, but she never invited me to another pot-luck, so it was sort of win-win for me.
I read a story once that mostly consisted of detailed instructions on how a woman should prepare and cook her lover. The part that stood out to me was cutting open the penis and inserting a properly shaped carrot to get the right lifelike look.