To start, preheat your oven to 350 degrees F Prep (2) 9 inch round cake pans with butter and a light dusting of flour You can line with parchment paper as well if desired, this will help the cake lift out of the pan much easier

Sift together 2 1/2 Cups cake flour 1 tsp. baking powder 1 tsp. baking soda 1 tsp. salt

In another bowl combine 1 Cup sour cream, room temperature 2 Tablespoons lemon zest 1/2 Cup lemon juice 1 tsp. vanilla extract

In a stand mixer blend 1 Cup unsalted butter, room temperature 2 Cups granulated sugar Mix until light and fluffy, then add 4 large eggs, room temperature Mix until everything is fully combined

Reduce the speed to low and slowly add in 1/3 of the flour mixture, followed by half of the sour cream mixture Repeat and continue mixing until all of the ingredients are incorporated

Pour batter equally into the floured 9 inch baking pans Bake 35 minutes or until a toothpick inserted into the center of the cake comes out clean

Making the Buttercream In a stand mixer beat 2 sticks unsalted butter, room temperature  2 1/4 Cups powdered sugar 1 tsp. vanilla extract 2 Tablespoons heavy cream 1 Tablespoon lemon zest 3 Tablespoons fresh lemon juice Yellow food coloring paste for color

Mix until the buttercream is light and fluffy Adjust the food coloring until the desired color has been achieved Decorate with a Wilton 2D tip to create rosettes