Preheat your oven to 350°F (175°C). Grease the two 9-inch round cake pans and line the bottoms with parchment paper.
In a large mixing bowl, cream together the softened butter and granulated sugar using an electric mixer until light and fluffy (about 3-4 minutes).
Add the eggs, one at a time, mixing well after each addition. Then stir in the vanilla extract.
In another bowl, whisk together the all-purpose flour, baking powder, and salt.
Gradually add the dry ingredients to the wet mixture, alternating with the whole milk. Begin and end with the dry ingredients, mixing until just combined.
Divide the batter evenly between the two prepared cake pans. Smooth the tops with a spatula.
Bake in the preheated oven for 25-30 minutes or until a toothpick inserted in the center comes out clean.
Remove the cakes from the oven and let them cool in the pans for about 10 minutes, then transfer them to a cooling rack to cool completely.
Once cooled, level the tops of the cakes if necessary. Place one layer on a serving plate and spread a layer of buttercream frosting on top.
Place the second cake layer on top and frost the top and sides of the cake with the remaining buttercream.
If desired, decorate with edible flowers or sprinkles for an elegant presentation.