Heather made this for us in early July and it was delicious. A few days ago, Elliott and Ann Nielson gave us some of their blackberries so we thought, "Black AND Blue Berry Cake. . . " So we added 50% more to the ingredients in the original recipe and cooked it in a 9"x12" pan.
3 tsp. lemon zest or more — zest from 1 large lemon
1 1/2 c + 1 tablespoon sugar**
1 1/2 egg, room temperature (scramble two eggs together: take out a tablespoon of egg [cook it in the microwave for a snack while you finish the cake])
1 1/2 tsp. vanilla
3 cups flour
1 TB baking powder
1 1/2 tsp. kosher salt
2 cups fresh blackberries