Spiced Hot Chocolate Brownies

1 cup (2 sticks) unsalted butter, softened, plus more for pan
1 cup (120 grams) all-purpose flour
2/3 cup Dutch-processed cocoa powder
1/4 cup whole milk powder
1 teaspoon ground cinnamon
1 teaspoon kosher salt
1/2 teaspoon cayenne pepper
12 ounces bittersweet chocolate, finely chopped (about 2 cups)
1 cup (200 grams) granulated sugar
1/2 cup (110 grams) packed light brown sugar
4 large eggs, at room temperature
2 teaspoons pure vanilla extract
 
Heat oven to 375°F. Grease a 13" x 9" metal baking pan with butter. Line with parchment, leaving an overhang on 2 opposite long sides, then grease parchment with butter. 

In a medium bowl, whisk flour, cocoa powder, milk powder, cinnamon, salt, and cayenne until combined.
 
In a medium saucepan over medium heat, melt butter until just bubbling. Remove from heat. Add chocolate, granulated sugar, and brown sugar, and mix until chocolate is glossy. Add eggs one at a time, stirring to blend after each addition, then stir in vanilla. Add chocolate mixture to flour mixture and fold in with a rubber spatula until no dry streaks remain. Pour batter into prepared pan.
 
Bake brownies until a tester inserted into the center comes out with a few moist crumbs attached, 25 to 30 minutes. Let cool in pan 15 minutes. Using parchment overhang, transfer to a wire rack and let cool completely.
 
Serves 12-16.
 
From Delish.com