Preheat oven to 350F

1. Butter and flour 3 – 6.5 Inch round pans (or 2 non-stick 9-inch cake pan) I like to put a round of parchment paper on the bottom of the pans to ensure a good release.
2. Cream the butter and sugar together until light and fluffy, scraping down the sides of the bowl as necessary. Beat in the egg yolks, one at a time.
3. Save the egg whites and in a separate bowl beat the egg whites until soft peaks form. Set to the side.
4. Whisk together the flour, baking powder, salt, and baking soda. Then add the flour mixture to the butter mixture alternating with the yogurt. Continue to mix until well combined. Note: be sure to scrape down the sides of the bowl to avoid lumps later.
5. Fold in the whipped egg whites, and when completed combined, fold in the berries.
6. Using a 1 cup measuring cup, divide the batter evenly between the three cake pans and even out the tops.
7. Bake the cakes on the same oven shelf for about 25 minutes, or until the center springs back when touched and the edges are just starting to turn golden. Don’t over-bake.
8. Let the cakes cool for 10 minutes before turning them out and cooling them completely on a rack.

Make the buttercream frosting:

1. In a large bowl or stand mixer cream together the butter and sugar until light and fluffy.
2. Add in the lemon juice and zest, with the beaters on slow, gradually and slowly add in the powdered sugar, continue until all the powdered sugar is well combined. Add more sugar if frosting is too thick, add more lemon juice if it’s too stiff. Take it slow when adding more juice as it doesn’t take much.
3. Frost the cake when completely cool. Add a generous amount of frosting in between the middle layers and finish frosting top and sides.