How to Make It
Make the cookies In a stand mixer fitted with the paddle, beat the butter until smooth, about 1 minute. Add the sugars and beat until light and fluffy. Beat in the egg and vanilla until smooth.
In a medium bowl, whisk the flour with the cornstarch and baking soda. With the machine on low, gradually add the dry ingredients to the wet until just incorporated. Fold in the chocolate chips. Cover and refrigerate for at least 1 hour and up to overnight.
Preheat the oven to 350° and line 12 cupcake molds with liners. Portion the dough into 1/3 cup-size balls, alternatively, use a 2.5-ounce scoop. Working one ball at a time, press your thumb into the center of the dough to form a deep indentation. Spoon about 1 tablespoon of the sprinkles or Nutella into the cavity and seal the cookie dough around the sprinkles, then transfer to the prepared cupcake pan. Repeat with the remaining cookie dough and sprinkles. Bake for 10 minutes, until golden brown and crisp around the edge. Transfer the cupcake pans to a baking rack and let cool completely.
Make the icing In a stand mixer fitted with the paddle, beat the butter until smooth. Beat in the vanilla. With the machine on, gradually add the confectioners’ sugar, 1/2 cup at a time, until incorporated and smooth. Beat in the crumbled cookies, if using. Spoon into a piping bag with a fluted tip and pipe the frosting onto the cookie bomb cupcakes. Garnish with more sprinkles and serve.