In a mixing bowl, whisk together the sugar, cocoa powder, and a pinch of kosher salt until evenly combined. Set aside.

Fill a medium pot almost halfway with water and bring it to a simmer over low heat. Place a heat-safe bowl on top of the pot, add the white chocolate chips, and stir until melted and smooth. Add ½ teaspoon of cinnamon and stir to combine.

Add a heaping spoonful of melted chocolate to each of the six molds, spreading it gently up the sides to form a shell. Freeze for 10 minutes until set.

Carefully remove the chocolate cups from the mold. Place them on a lined baking sheet, ready for filling.

Fill three of the chocolate halves with 2 tablespoons of hot cocoa mix, ½ teaspoon of cinnamon, and 5-6 mini marshmallows.

Gently melt the rims of the other three chocolate halves over the pot of warm water to create a sticky surface. Place one of the filled halves under a melted rim, pressing down lightly to seal.

Drizzle any remaining melted chocolate over the tops and sprinkle with extra cinnamon or festive sprinkles if desired.

To make hot chocolate, drop a snickerdoodle bomb into a mug and slowly pour about 1½ cups of hot milk over it. Give it a stir and watch the magic happen!