Preheat your oven to 350°F (175°C). Grease and flour the two 9-inch round cake pans.
In a mixing bowl, combine the softened butter and granulated sugar. Beat the mixture with a hand mixer or stand mixer until it's light and fluffy.
Add the eggs, buttermilk, and vanilla extract to the butter-sugar mixture. Mix until fully combined.
In another bowl, whisk together the flour, baking powder, and salt.
Gradually add the dry ingredients to the wet mixture, mixing until just combined.
Divide the batter evenly into two bowls. Color one bowl with pink food coloring and the other with blue food coloring, adjusting the amount until you achieve your desired shades.
Pour the pink batter into one prepared cake pan and the blue batter into the other. Bake in the preheated oven for 25 minutes, or until a toothpick inserted in the center comes out clean. Let the cakes cool in the pans for about 10 minutes, then turn them out onto a cooling rack to cool completely.
While the cakes are cooling, prepare the whipped cream. In a mixing bowl, beat the heavy whipping cream, powdered sugar, and vanilla extract until soft peaks form.
Once the cakes have cooled, level the tops if necessary. Place one layer on a serving plate and pipe or spread a layer of whipped cream on top. If desired, add additional coloring to the whipped cream, or add sprinkles.
Place the second cake layer on top and cover the entire cake with the remaining whipped cream. Decorate as desired.