Line a 24-cup mini muffin tin with 24 mini muffin liners and set the tray aside with room in the freezer for later.

If using a chocolate bar, break or chop the 8 oz dark chocolate into small pieces so it melts evenly.

Melt the chocolate either by microwave or double boiler: - Microwave: heat in a microwave-safe bowl in 30-second intervals, stirring between each interval, until just melted and smooth. - Double boiler: place the chocolate in a heatproof bowl set over (but not touching) simmering water in a saucepan. Stir occasionally until melted, then remove the bowl from the heat.

Spoon or drizzle some melted chocolate into each liner and rotate the tin or use the back of the spoon to spread the chocolate up the sides of each liner, forming a chocolate shell. Reserve the remaining melted chocolate in the bowl.

Transfer the tray to the freezer until the chocolate shells are set and no longer tacky, about 5 minutes.

Divide the 1/4 cup smooth peanut butter evenly among the 24 set shells, placing the peanut butter in the center of each shell. Then divide the 1/4 cup jelly or jam evenly and add it on top of the peanut butter in each cup.

Spoon the remaining melted chocolate over each filled cup to fully cover the peanut butter and jelly and seal each cup. If the chocolate has begun to harden, briefly rewarm it until pourable before topping.

Sprinkle a small pinch of flaked or coarse salt on each cup if desired.

Return the tray to the freezer until the tops are firm, about 5–10 minutes. Remove the cups from their liners and enjoy immediately, or store chilled.