Preheat oven to 350 degrees F. Line two baking sheets with parchment paper. 

Melt chocolate and butter in a double boiler. Set aside to cool slightly.

In a large mixing bowl using a hand mixer or in the bowl of a stand mixer fitted with the whisk attachment, beat eggs with sugars and vanilla on medium/high speed for 5 minutes. 

Add in the melted chocolate/butter mixture and mix until combined.

Stir in flour, cocoa powder, baking powder, and salt.

Use a medium sized cookie scoop to drop 1 ½ tbsp size balls onto the prepared baking sheets. You should be able to fit 12 cookies per sheet.

Bake for 12 minutes. Remove cookies from oven and allow to cool completely on a wire rack.

Once cookies are completely cool, place a large scoop of ice cream and sandwich it between 2 cookies. Freeze the sandwiches for 30 minutes.

Melt the chocolate chips in a double boiler. Dip the frozen ice cream cookie sandwiches into the chocolate and then sprinkle with topping of choice. Return cookies to freezer until ready to eat.