Preheat your oven to 350°F (175°C).

Grease and flour two 9-inch round cake pans.

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

Add the eggs one at a time, mixing well after each addition. Stir in the vanilla extract.

In another bowl, combine the flour, baking powder, and salt.

Gradually add the dry ingredients to the wet mixture, alternating with the milk. Mix until just combined.

Divide the batter evenly between the two prepared cake pans.

Bake in the preheated oven for 25-30 minutes, or until a toothpick inserted into the center comes out clean.

Let the cakes cool in the pans for 10 minutes before transferring them to a wire rack to cool completely.

Once the cakes are completely cool, spread a layer of buttercream frosting on top of one cake layer, and place the other layer on top.

Frost the top and sides of the cake with buttercream, smoothing it out as you go.

Use food coloring to tint small portions of the buttercream if you want to create different colors for decorative effects.

Decorate the cake with vintage decorations as desired.