Chocolate peanut butter cups
First, create the universe. Then, procure melting chocolate. I buy mine from AC Moore in Somerville, but you can also temper your own if you have a food thermometer. Instructions for that. Even the dark chocolate from AC Moore has milk traces in it, so you'll have to temper your own if you want vegan candy.
Recipe: Heat chocolate until it melts. It should stay melted for as long as you need it to if you keep stirring and don't let it harden. Use a mold (also findable at AC Moore, or I suppose you could 3D print a cooler shape) and coat bottoms and sides of mold with chocolate. Stick it in the freezer until hard, usually 2-3 minutes. Take it out and fill with peanut butter (you can add powdered sugar to peanut butter to get a sweeter center) and fill in the rest of the mold with chocolate. Stick back in freezer til hard, 5-10 minutes. Dump out of mold, it should come easily.
You should be able to store the cups at room temperature or in the fridge, whichever you prefer.