Preheat oven to 350°F (175°C) and line two baking sheets with parchment paper.

Cream the softened butter and granulated sugar in a large bowl until fluffy.

Add eggs and vanilla extract; mix until fully combined.

In another bowl, whisk together flour, cocoa powder, baking soda, and salt.

Gradually add dry ingredients to the wet mixture and mix until a soft dough forms.

Scoop tablespoon-sized dough onto the baking sheets, spacing evenly.

Bake for 10 minutes, then press a halved marshmallow into each cookie.

Return to oven for 2 more minutes, just to soften the marshmallows.

In a microwave-safe bowl, melt chocolate chips with heavy cream in 30-second bursts, stirring in between, until smooth.

Spoon chocolate glaze over the marshmallows and immediately top with sprinkles.

Let cookies cool on a wire rack until the glaze sets.