- Oat Crust:
- 2 1/2 cups rolled oats
- 3/4 cup all-purpose flour
- 3/4 cup packed brown sugar
- 1/2 teaspoon baking soda
- 1/4 teaspoon salt
- 3/4 cup unsalted butter, melted
- Brownies:
- 3 cups white sugar
- 1 cup unsalted butter, melted
- 1 tablespoon vanilla extract
- 4 eggs
- 1 1/2 cups all-purpose flour
- 1 cup unsweetened cocoa powder
- 1 teaspoon salt
- 1 cup semisweet chocolate chips
- Preheat oven to 350 degrees F (175 degrees C). Grease a 9×13-inch baking dish.
- Mix oats, 3/4 cup flour, brown sugar, baking soda, and 1/4 teaspoon salt together in a bowl. Stir 3/4 cup melted butter into oat mixture until evenly coated. Measure 3/4 cup oat mixture and reserve for later. Press remaining oat mixture into the prepared baking dish.
- Bake in the preheated oven until lightly browned, about 5 minutes.
- Combine white sugar, 1 cup melted butter, and vanilla extract in a bowl. Beat eggs, 1 at a time, into sugar mixture, mixing well after each addition, until thoroughly blended.
- Sift 1 1/2 cups flour, cocoa powder, and 1 teaspoon salt together in a bowl; stir into sugar-egg mixture just until batter is blended. Fold chocolate chips into batter; pour over oat crust. Sprinkle reserved oat mixture over batter.
- Bake in the preheated oven until a toothpick inserted in the center of the brownies comes out clean, 35 to 40 minutes.