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One chocolate cookie spread with chocolate ganache and sprinkled with rainbow chips on white parchment paper.

Cosmic Brownie Cookies

Yield: 36 to 36 cookies
Prep Time: 45 minutes
Cook Time: 10 minutes
Total Time: 55 minutes

Ingredients

  • 1 cup (227 g) butter, softened to room temperature (not too soft!)
  • 1 ½ cups (318 g) packed light brown sugar
  • ½ cup (106 g) granulated sugar
  • 1 teaspoon baking powder
  • ¾ teaspoon table salt
  • ½ teaspoon baking soda
  • 2 large (100 g) eggs
  • 1 tablespoon vanilla extract
  • 2 ¾ cups (390 g) all-purpose flour
  • ⅔ cup (57 g) Dutch-process or natural, unsweetened cocoa powder

Topping:

  • ½ cup heavy cream
  • 1 ½ cups (255 g) semisweet chocolate chips
  • Rainbow candy coated mini chocolate chips (see note)

Instructions 

  • Preheat oven to 350 degrees F (see note!). Line half sheet pans with parchment paper; set aside.
  • For the cookies, in a bowl with an electric handheld mixer or in the bowl of a stand mixer fitted with the paddle attachment, cream together the butter, brown sugar, granulated sugar, baking powder, salt and baking soda until the mixture is light and fluffy, 1 to 2 minutes.
  • Add the eggs and vanilla. Mix until well-combined, scraping down the sides of the bowl as needed.
  • Add the flour and cocoa powder. Mix until evenly combined and no dry streaks remain.
  • Scoop the cookie dough into 2-tablespoon size balls and roll until smooth (see note for larger cookies). Place several inches apart on the prepared baking sheets.
  • Bake for 10 to 11 minutes until the cookies are lightly puffed and set around the edges but still soft in the center.
  • Optional: in my ovens, the cookies are slightly domed on top after baking. Immediately out of the oven, I use a flat-bottomed glass to gently press to an even thickness. Don't smash them flat! Just press the domed top so the cookie is still thick but even across the top. This makes frosting the cookies easier (and prettier) and also gives the cookie an extra fudgy center.
  • Let the cookies cool for several minutes on the baking pans and then remove them to a cooling rack to cool completely.
  • For the ganache, place the chocolate chips in a medium bowl.
  • Heat the heavy cream until steaming and bubbles form around the edges. Pour the cream over the chocolate chips, pressing the chocolate chips to submerge them in the cream. Let sit for 2 to 3 minutes until the chocolate chips are melted and then stir or whisk until the mixture is glossy and smooth.
  • Let the ganache cool for 5 to 10 minutes to thicken slightly.
  • Frost the cooled cookies with a dollop of ganache and sprinkle with rainbow candy coated chips.
  • Serve immediately while the ganache is soft or let the cookies sit at room temperature for an hour or so until the ganache sets. The cookies are delicious served at room temperature and terribly delicious served chilled.

Notes

Rainbow Chips: these are the rainbow chips I use for the *cosmic brownie* vibe (if the ones at the link aren't available, just search "rainbow baking chips" online). Mini M&Ms, flat colorful sprinkles, crips chocolate pearls or other colorful sprinkles can be used as a substitute for the rainbow chips.  
Baking Temperature: if your oven bakes cool (or your cookies tend to flatten), increase the baking temperature to 375 degrees F and bake for about a minute less (keep an eye on the cookies so they don't over bake). 
Size of Cookies: I use a #40 medium cookie scoop to portion out about 2 tablespoons of dough per cookie. These cookies can be made larger with a #20 cookie scoop. Bake for 1 to 2 minutes longer for larger cookies.