Preheat oven to 350°F (175°C). Grease and flour two 8-inch round cake pans or three 6-inch round cake pans. Line the bottoms with parchment paper.

In a medium bowl, whisk together the sifted cake flour, baking powder, baking soda, and salt. Set aside.

In a large bowl, using an electric mixer, cream together the softened butter and granulated sugar on medium-high speed until light and fluffy, about 3-5 minutes.

Add the eggs one at a time, beating well after each addition. Scrape down the sides of the bowl as needed. Beat in the vanilla extract.

With the mixer on low speed, gradually add the dry ingredients to the wet ingredients in three additions, alternating with the buttermilk, beginning and ending with the dry ingredients. Mix until just combined; do not overmix.

Divide the batter evenly among the prepared cake pans.

Bake for 25-30 minutes, or until a wooden skewer inserted into the center comes out clean.

Let the cake layers cool in the pans for 10-15 minutes before inverting them onto a wire rack to cool completely.

To make the Vanilla Buttercream: In a large bowl, cream the softened butter with an electric mixer until smooth.

Gradually add the sifted powdered sugar, one cup at a time, mixing on low speed until combined.

Add the heavy cream, vanilla extract, and pinch of salt. Increase speed to medium-high and beat until light and fluffy, about 3-5 minutes. Add more cream if needed to reach desired consistency.

Once the cake layers are completely cool, level them if necessary using a serrated knife.

Place one cake layer on a serving plate. Spread about 1/3 of the buttercream on top. Add the second layer, spread another 1/3 of the buttercream. If using three layers, repeat.

Use the remaining buttercream to frost the sides and top of the entire cake. Decorate as desired.

Slice and serve. Enjoy your delicious homemade vanilla cake!