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

In a large mixing bowl, use an electric mixer to cream butter and sugars together until creamy and well combined.

Add egg, egg yolk, and vanilla extract and stir until combined.

In a separate, medium-sized bowl whisk together flour, cocoa powder, baking powder, baking soda, and salt.

Gradually add dry ingredients to wet ingredients, stirring until completely combined.

Scoop cookie dough by 2 Tablespoon-sized scoops and roll between your palms to make a smooth ball. Place on baking sheet, spacing cookies at least 2” (5cm) apart and bake in 350F (175C) oven for 10-11 minutes.

Within one minute of removing cookies from the oven, gently flatten the surface of the cookie using a 1-cup measuring cup (this will give you a smooth surface for decorating the cookie). While cookies are cooling, prepare your frosting.

For the frosting Combine cream cheese and butter in a large mixing bowl and use an electric mixer to beat until smooth and creamy.

Add vanilla extract and salt, stir until combined.

With mixer on low speed, gradually add powdered sugar until completely combined.

Add cocoa powder and stir until completely incorporated and frosting is uniform.

Assembly Spread or pipe frosting onto cooled cookies (I like to use a piping bag fitted with an open tip to pipe the frosting then smooth it with an offset spatula).

Sprinkle cookie crumbs evenly over the frosting then gently nestle 1-2 gummy worms on top of the frosting. Enjoy!