Preheat your oven to 350°F (175°C) and grease a 9-inch round cake pan with butter or non-stick spray. Dust with flour to ensure easy release.

In a large mixing bowl, whisk together the flour, baking powder, cocoa powder, and salt until well combined.

In another bowl, cream the butter and sugar until light and fluffy. Add the eggs one at a time, beating well after each addition, then mix in the vanilla extract.

Gradually add the dry ingredients to the wet ingredients, stirring until just combined. Avoid overmixing to keep the batter tender.

Divide the batter into three bowls. Add blue, purple, and pink gel food coloring to each bowl, mixing until the desired shades are achieved.

Pour the colored batters into the prepared pan in alternating layers. Use a skewer to swirl the colors together gently, creating a galaxy effect.

Bake in the preheated oven for 45-50 minutes or until a toothpick inserted into the center comes out with only a few moist crumbs. Let cool in the pan for 10 minutes.

Transfer the cake to a wire rack to cool completely before slicing. This ensures the cake sets properly and the colors remain vibrant.

Slice the cake into 8 pieces and serve with a scoop of vanilla ice cream or a dollop of whipped cream for added indulgence.

Store any leftover cake in an airtight container at room temperature for up to 3 days. For longer storage, refrigerate for up to a week.