Preheat your oven to 350°F (175°C) and grease a 9x9-inch baking pan or line it with parchment paper for easy removal.
In a mixing bowl, combine the flour, cocoa powder, granulated sugar, baking powder, and salt. Whisk together until combined.
In a separate bowl, beat the softened butter until creamy. Add the egg and 1 teaspoon of vanilla extract, mixing well until smooth.
Gradually add the dry ingredients to the wet ingredients, mixing until a dough forms.
Take about 2/3 of the dough and press it evenly into the bottom of the prepared baking pan. Set aside the remaining dough for topping.
In a bowl, mix the ricotta cheese, powdered sugar, 1 teaspoon of vanilla extract, mini chocolate chips, and orange zest (if using) until well combined.
Evenly spread the ricotta mixture over the cookie base in the baking pan.
Crumble the reserved dough over the filling to create a topping that resembles a crumble.
Place the pan in the preheated oven and bake for 25-30 minutes or until the top is set and slightly firm to touch.
Allow the squares to cool in the pan for 10 minutes, then transfer them to a wire rack to cool completely before slicing into squares.
Notes
Dust the top of the squares with additional powdered sugar before serving. Arrange them on a decorative plate and serve with a side of fresh berries for added color and flavor.