Preheat the oven to 350 degrees F. Grease the bottom and sides of three 8 inch round cake pans or springform pans with butter and line the bottom of each pan with a round piece of parchment paper. To ensure even baking, place a bake even strip around the pan. Set aside.

In a medium bowl, whisk together the all purpose flour, lemon zest, baking powder, and salt, set aside.

Using an electric mixer, beat the butter and sugar on medium-high until fluffy, 2 to 3 minutes. Beat in the eggs and vanilla extract, scraping down the sides of the bowl as needed.

Reduce mixer speed to low and add the flour mixture in 3 additions and the milk in 2 additions, beginning and ending with the flour mixture. Mix on low just until combined.

Divide the batter evenly among the pans, with about 1 & 3/4 cups batter in each pan. Place the pans in the oven. If they don’t all fit on one rack, place 2 on the upper rack and 1 on the bottom rack. Be sure to check the bottom one as it will bake faster or rotate the pans halfway through. Bake for 23-27 minutes or until a toothpick inserted in the center comes out clean.

Once the cakes are done, allow them to cool in the pan on a cooling rack for 10-20 minutes. After cooling, carefully remove the cake from the pan. If using a springform pan, remove the sides and bottom. Allow the cake to cool completely on a cooling rack. Once cool, remove the parchment paper round from the bottom of the cake. If you need to level the top of your cakes, do so now using either a cake lever or knife. If you’re assembling the cake later, wrap each cake layer really well in plastic wrap and place them in the refrigerator, for up to 3 days.

Place room temperature unsalted butter in a mixing bowl. Use an electric mixer on medium-low and beat the butter for 1-2 minutes, until whipped and fluffy.

Add in the fresh lemon juice, salt, and gradually add in the powdered sugar (start with 2 cups), beat on low for 60 seconds. Add more powdered sugar to taste (up to 4 additional cups) and continue to mix on low until fluffy and smooth.

If the frosting is too thick, add a splash more lemon juice, beat until creamy.

I like to assemble my cakes on a turntable. Spread a small amount of buttercream on a 8 inch round cardboard circle or cake plate if skipping the cardboard circle. Place the first layer on top of the cardboard, lightly push down to adhere the cake to the frosting.

Evenly spread 3/4 cup frosting on top of the first layer.

Add the second layer of cake, lightly pushing down. Evenly spread 3/4 cup frosting on top of the second layer.

Add the third layer of cake, lightly pushing down. Once all of the layers are stacked, it’s time to do a crumb coat. The crumb coat will help seal the crumbs in. Using your offset spatula, spread a thin layer of buttercream around the sides and top of the cake.

Place the entire cake in the fridge for 20 minutes.

Spread the remaining frosting on the sides and top of the cake. Slice and serve. Cover leftover cake tightly with plastic wrap and store on the counter for up to 3 days.