Preheat your oven to 350°F and line a baking sheet with parchment paper. Chop the 8 oz of semi-sweet chocolate into 1/2-inch pieces and chop the 8 oz of white chocolate into small pieces—this ensures even melting later. Measure out the crushed peppermint candy, making sure the pieces are finely crushed to about 1/8-inch size for even distribution. Having everything prepared before you start mixing will keep your workflow smooth and prevent the melted chocolate from cooling while you hunt for ingredients.

In a medium bowl, whisk together the flour, Dutch-processed cocoa powder, baking powder, and salt. Set this mixture aside. Whisking the dry ingredients together ensures the baking powder and cocoa powder are evenly distributed throughout the flour, which guarantees consistent rise and chocolate flavor in every cookie.

In a large mixing bowl, beat the 2 large eggs with the packed brown sugar and granulated sugar for 3-5 minutes until the mixture becomes light, pale, and fluffy. This aeration is crucial—it creates tiny air pockets that give these cookies their distinctive brownie-like texture rather than a dense, flat result. Don't skip this step; the beaten eggs are what makes these cookies special.

Microwave the chopped semi-sweet chocolate (from Step 1) and softened butter together in 30-second intervals, stirring between each interval, until completely smooth—this usually takes 1-2 minutes total. Let it cool for 1-2 minutes so it's no longer steaming, then add the vanilla extract and peppermint extract. Gently fold this chocolate mixture into the egg mixture from Step 3 until just combined. I prefer to let the melted chocolate cool slightly before mixing to avoid cooking the eggs.

Fold the dry ingredient mixture from Step 2 into the chocolate mixture from Step 4 until just combined—don't overmix, as this can make the cookies tough. Gently fold in the semi-sweet chocolate chips. The dough should be thick and fudgy. Scoop dough into 1.5-tablespoon balls onto the prepared baking sheet, spacing them about 2 inches apart to allow for slight spreading.

Bake in the preheated 350°F oven for 10-12 minutes. The cookies should look slightly underbaked when you pull them from the oven—the edges will be set but the centers should still look a bit soft. This is intentional; they'll continue cooking as they cool on the sheet for 2-3 minutes before transferring to a wire rack. The residual heat creates that signature fudgy brownie texture.

Once the cookies are completely cooled, microwave the chopped white chocolate (from Step 1) and shortening together in 30-second intervals, stirring between each interval, until smooth and glossy. Stir in the peppermint extract. The shortening is key here—it keeps the white chocolate coating smooth and prevents it from becoming thick and chalky. Dip each cooled cookie halfway into the white chocolate coating, then immediately sprinkle the crushed peppermint candy on the wet coating so it adheres. Set on parchment paper to set. The finished cookies will have a beautiful contrast of dark brownie cookie with a crisp white chocolate peppermint shell.