Ingredients
6 tablespoons unsalted butter, room temperature
3/4 cup packed light-brown sugar
1 large egg
1 teaspoon pure vanilla extract
1 cup all-purpose flour
2 tablespoons Dutch-process cocoa powder
1/2 teaspoon baking soda
1/2 teaspoon coarse salt
1 1/2 cups (10 ounces) semisweet chocolate chips
Preparation
Preheat oven to 350 degrees. In a large bowl, mix butter and sugar with a wooden spoon. Stir in egg and vanilla, then flour, cocoa, baking soda, and salt. Stir in chips.
Transfer batter to a 10-inch ovenproof nonstick skillet; smooth top. Bake until just set in center and pulling away from sides, 20 to 22 minutes. Let cool 10 minutes; loosen edges. Turn out onto a wire rack. Reinvert onto a plate, slice, and serve.
