Preheat the oven to 350°F (175°C) and grease the bundt pan.

In a mixing bowl, cream together the butter and sugar until light and fluffy.

Add the eggs one at a time, mixing well after each addition.

Stir in the milk and vanilla extract.

In a separate bowl, combine the flour and baking powder.

Gradually add the dry ingredients to the wet ingredients, mixing until just combined.

Divide the batter into separate bowls and add food coloring to each, mixing until desired colors are achieved.

Spoon the colored batter into the prepared bundt pan, swirling gently to create a marbled effect.

Bake in the preheated oven for 40-45 minutes or until a toothpick inserted comes out clean.

Allow to cool in the pan for 10 minutes before inverting onto a wire rack to cool completely.