Chocolate Chip Cookie Cake

Name: Chocolate Chip Cookie Cake
Ingredients: For the cake; Baking spray; 3 cups all-purpose flour; 2 teaspoons baking powder; 1 teaspoon baking soda; 1 teaspoon salt; 2 sticks (8 ounces) unsalted butter, softened; 2 cups packed light brown sugar; 4 large eggs, at room temperature; 2 teaspoons pure vanilla extract; 1 1/4 cups buttermilk, at room temperature; 8 ounces bittersweet chocolate, chopped; 1/2 cup walnuts, chopped (optional); For the chocolate drizzle; 1/2 cup heavy cream; 1 tablespoon light corn syrup; 1/8 teaspoon salt; 3 ounces bittersweet chocolate, chopped