Preheat oven to 350 F. Grease and flour a 9-inch bundt cake pan. Set aside. In a large bowl using either a hand or stand mixer, beat softened butter with sugar until fluffy.
Add in eggs and beat until smooth. Add in flour and beat until all of the flour is incorporated into the batter. Divide the cake batter evenly between thee separate bowls.
Add in red food coloring to one bowl and mix until fully red. Mix blue food coloring into another bowl until fully blue.
Add the cake batter into the prepared cake pan in a layer of red, white and blue. Bake for 50-60 minutes. Let cool completely.
For the vanilla glaze, whisk milk and vanilla extract into the powdered sugar until smooth. Drizzle over cake.
