Preheat the Oven & Prepare the Pan:
Preheat your oven to 350°F (175°C). Grease and flour a 9-inch round cake pan, or line it with parchment paper.

Make the Cake Batter:
In a large bowl, beat the softened butter and sugar together until light and fluffy (about 3-4 minutes).
Add the ricotta cheese and eggs, continuing to beat until the mixture is smooth and creamy.

Combine Dry Ingredients:
In a separate bowl, whisk together the all-purpose flour, baking powder, cocoa powder, and a pinch of salt.

Mix the Wet and Dry Ingredients:
Gradually add the dry ingredients to the wet mixture and mix until well combined. If the batter is too thick, add a splash of milk to achieve a smoother consistency.

Prepare the Chocolate Swirl:
Divide the batter in half. In one half, fold in the chocolate chips and an additional tablespoon of cocoa powder to create the chocolate batter.

Create the Marble Effect:
Spoon alternating dollops of vanilla and chocolate batter into the prepared cake pan. Use a knife or skewer to gently swirl the batters together, creating the marble effect.

Bake:
Bake for 30-35 minutes, or until a toothpick inserted into the center comes out clean.

Cool the Cake:
Let the cake cool in the pan for 10 minutes before transferring it to a wire rack to cool completely.

Optional Finishing Touches:
Once the cake has cooled, you can dust it with powdered sugar or drizzle it with melted chocolate for extra flair.