Preheat the Oven: Start by preheating your oven to 350°F (176°C). Grease and flour two 9-inch round cake pans.
Mix Dry Ingredients: In a medium bowl, whisk together the flour, baking powder, and salt. Set aside.
Cream Butter and Sugar: In a large mixing bowl, beat the unsalted butter and sugar together until light and fluffy, approximately 3-5 minutes.
Add Eggs and Vanilla: Add the eggs one at a time, mixing well after each addition. Stir in the tablespoon of vanilla extract.
Combine Mixtures: Gradually add the dry mixture to the butter mixture, alternating with the milk. Start and end with the dry mix, ensuring everything is well combined.
Bake: Divide the batter evenly between the prepared pans and bake for 25-30 minutes, or until a toothpick inserted into the center comes out clean.
Make Frosting: While the cakes are cooling, prepare the frosting by beating the room temperature butter until creamy. Gradually mix in the powdered sugar, vanilla, and heavy cream until the frosting reaches a smooth, spreadable consistency.
Frost the Cake: Once the cakes have cooled completely, place one layer on a serving plate and frost the top. Place the second layer on top and frost the top and sides of the cake.