Preheat your oven to 350°F (175°C) and prepare a 9x9-inch baking pan by greasing it or lining it with parchment paper.
In a large mixing bowl, combine the all-purpose flour, unsweetened cocoa powder, granulated sugar, baking powder, and salt. Whisk until well blended.
In a separate bowl, beat the softened butter until creamy and fluffy. Add the egg and 1 teaspoon of vanilla extract, mixing until smooth.
Gradually add the dry ingredients to the wet mixture, stirring until a soft dough forms.
Press two-thirds of the dough evenly across the bottom of the prepared baking pan, reserving the remaining dough for topping.
In another bowl, combine the ricotta cheese, powdered sugar, 1 teaspoon of vanilla extract, mini chocolate chips, and optional orange zest. Stir until creamy.
Spread the ricotta mixture over the cookie base in the baking pan.
Crumble the remaining dough over the ricotta filling to create a topping.
Bake for 25-30 minutes until the top is set and slightly firm.
Allow to cool in the pan for 10 minutes, then transfer to a wire rack to cool completely before slicing.
Notes
Dust with powdered sugar before serving for an elegant touch.