📖 Instructions

1. Get Ready: Preheat your oven to 350°F (175°C). Grease and flour your baking pans. I usually go with two 9-inch round pans, but square ones work too!
2. Cream Together: In a large mixing bowl, cream together the butter and sugar until light and fluffy. An electric mixer works best for this. Don't skimp on this step, as it's crucial for the cake's texture.
3. Add Eggs and Vanilla: Beat in the eggs one at a time, then stir in the vanilla extract. Make sure each egg is fully incorporated before adding the next.
4. Combine Dry Ingredients: In a separate bowl, whisk together the flour, baking powder, and salt. This ensures that the baking powder is evenly distributed throughout the flour.
5. Alternate Wet and Dry: Gradually add the dry ingredients to the wet ingredients, alternating with the milk. Begin and end with the dry ingredients. Mix until just combined; be careful not to overmix.
6. Divide the Batter: Divide the batter in half. In one bowl, stir in the melted chocolate or hot chocolate mix. In the other bowl, leave the batter plain.
7. Marble Time!: Spoon alternating dollops of each batter into the prepared pans. Swirl the batters together with a knife or skewer. Don't over-swirl, or you'll lose the distinct marble effect.
8. Bake: Bake for 30-35 minutes, or until a toothpick inserted into the center comes out clean. If the top starts to brown too quickly, tent it with foil.
9. Cool: Let the cakes cool in the pans for 10 minutes before inverting them onto a wire rack to cool completely. This prevents them from sticking to the pan.
10. Frost (Optional): Once the cakes are completely cool, frost with your favorite frosting. A simple vanilla buttercream or chocolate ganache works perfectly.