Soft butter, for greasing the pan
Flour, for dusting the buttered pan
4 large eggs
1 cup sugar, sifted
1 cup brown sugar, sifted
8 ounces melted butter
11/4 cups cocoa, sifted (use half regular and half dark)
2 teaspoons vanilla extract
1/2 cup flour, sifted
1/2 teaspoon kosher salt
Preheat the oven to 300 degrees F. Butter and flour an 8-inch square pan.
Sift (in a food processor) the sugars together first and put in one bowl and then the rest of the dry ingredients together in another bowl. In a mixer fitted with a whisk attachment, beat the eggs at medium speed until fluffy and light yellow. Add vanilla, and sugar mixture. Combine the rest of the dry ingredients and add in thirds, alternating between dry and butter. The goal is even distribution of everything.
Pour the batter into a greased and floured 8-inch square pan and bake for 45 minutes. Check for doneness with the tried-and-true toothpick method: a toothpick inserted into the center of the pan should come out clean. When it’s done, remove to a rack to cool. Resist the temptation to cut into it until it’s mostly cool.