Brownies with Shiny, Crackly Tops

Preheat the oven to 350 degrees F (175 degrees C). Grease a 9x13-inch baking pan with shortening.

Combine chocolate and butter in a large, heavy saucepan over low heat, stirring constantly, until melted, about 5 minutes. Remove from heat.

Whisk flour, cocoa, and salt together in a bowl.

Beat eggs in a large bowl with an electric mixer on high speed until well blended. Gradually add white and brown sugars; beat until tripled in volume and very pale yellow, at least 10 minutes. The mixture should leave ribbons when you lift the beaters. Fold in the chocolate-butter mixture and vanilla extract, then flour mixture. Pour into the prepared pan.

Bake in the preheated oven until a toothpick inserted into the center comes out almost clean, 28 to 32 minutes. Cool before cutting into 16 brownies.