Preheat oven to 350 F / 175 C. Grease and flour your cake tin.
In a large bowl, beat butter and sugar with a mixer at a medium speed until fluffy. Add the eggs one at the time, beating well after each addition.
Gradually add flour to butter mixture alternately with milk, beating just until combined after each addition. Stir in the vanilla and the blue- and raspberries.
Pour batter into prepared tin. Bake until a wooden pick inserted in center comes out clean. Let cool in tin for 10 minutes. Remove from tin, and let cool completely on a wire rack.