Arrange your molds or wrappers: place silicone peanut-butter-cup molds on a flat tray or spread about 30–32 mini foil cupcake wrappers on a baking sheet or in a shallow pan.

Melt about half of the dark chocolate candy melts (about 1 pound of the 2 pounds) using the package instructions or one of these methods: (a) double boiler — place a heatproof bowl over a pan of simmering water and stir until smooth, or (b) microwave — heat at 50% power, stirring every 15–30 seconds until melted and smooth.

Spoon or transfer the melted chocolate into a squeeze bottle or piping bag (or use a spoon). Fill each mold or wrapper about halfway with chocolate. Use a small brush or the back of a spoon to spread chocolate partway up the sides so each cup has a chocolate shell.

Chill the filled molds in the refrigerator until the chocolate is set and firm, about 10–20 minutes.

Portion the peanut butter: dollop peanut butter into the center of each chocolate shell. Use approximately 1/2 teaspoon for small peanut butter cups, about 1 teaspoon for large cups, or about 1 tablespoon for the mini foil wrappers. (You can also divide the full 1 cup of peanut butter evenly among your cups.)

Melt the remaining chocolate melts using the same method as Step 2.

Use a spoon, squeeze bottle, or piping bag to cover each peanut butter dollop with the remaining melted chocolate, sealing the edges so no peanut butter is exposed. Tap the tray gently on the counter to level the tops and release air bubbles.

Let the tops set slightly (a few minutes), then sprinkle with coarse sea salt, chocolate sprinkles, or mini chocolate chips as desired.

Refrigerate until fully firm, about 15–30 minutes. Remove the cups from the molds or wrappers and serve or store.