For the Monster Brookies

• Melt the chocolate. Place the chocolate in the top of a double boiler or in a heatproof bowl set over a medium, heavy-bottomed saucepan filled with a few inches of simmering water (be sure the bottom of the bowl does not touch the water). Cook over medium heat to melt the chocolate, using a heatproof rubber spatula to stir the mixture and scrape the sides of the bowl occasionally, about 10 minutes. Set the double boiler or bowl on a wire rack and let the chocolate cool slightly while you prep the other ingredients.
• Prep your oven and pans. Position a rack in the center of the oven and preheat the oven to 350°F. Line 2 half sheet pans with parchment paper.
• Make the cookie dough. In a medium bowl, whisk together flour, cocoa powder, baking powder, and salt.
• In the bowl of a stand mixer fitted with the paddle attachment, combine the butter and sugar. Beat on medium-high until light, fluffy, and doubled in volume, 2 to 3 minutes, using a rubber spatula to scrape down the bottom and sides of the bowl as necessary. Reduce the mixer to low and add the eggs one at a time, adding the next egg only after the previous one is fully incorporated, scraping down the bottom and sides of the bowl after each addition. Add the vanilla and beat until just combined. Scrape down the bottom and sides of the bowl.
• With the mixer on low, slowly pour in the melted chocolate and beat until just combined. Gradually add the dry ingredients and beat until just combined. Scrape down the bottom and sides of the bowl once more, and beat on low for an additional 30 seconds.  Increase the mixer to medium-low, add the Reese's Pieces all at once, and beat until the chocolate is evenly distributed throughout, about 1 minute.
• Rest the dough. Let the dough rest for about 5 to 10 minutes before you start scooping out the cookies. The batter will be very soft at first, but will firm up quickly as it sits.
• Assemble the cookies. Use a 3-tablespoon cookie dough scoop to portion the dough out into cookie dough balls. At this point, you should have around 22 cookie dough balls. Take two of the balls and squish them together, creating a giant cookie dough ball. Repeat with the remaining cookie dough balls. You should end up with 12 giant cookie dough balls. Place the cookies at least 3 inches apart on the prepared sheet pans.
• Bake the cookies. Bake one pan at a time for 14 to 16 minutes, or until the edges have set but the cookies are cracked all over their tops.
• Finish assembling the cookies. Place the sheet pan with the cookies on a wire rack and, working quickly, gently press 2 to 3 candy eyes on each cookie. Cool the cookies on the pan on a wire rack for 20 minutes, or until the edges and bottoms of the cookies have set and feel firm to the touch. Repeat with the remaining cookie dough.
• Serve and store. Serve warm or at room temperature. The cookies can be stored in an airtight container or zip-top bag at room temperature for up to 3 days.