Blueberries are a big seller at the farmers market. I have done blueberry muffin, blueberry lemon loaf, and several different blueberry cakes in the month of June. This is my favorite cake and it sells well when I replace the lemon blueberry loaf with another loaf like orange weekend cake. You don't want too many blueberry items, you still need diversity in product selection.
Preheat oven to 350°.
In a small bowl mix 2/3 cup flour with 5 tablespoons butter, 1/4 cup sugar, 1/3 cup brown sugar, 1/4 teaspoon salt and 1/2 cup chopped walnuts. Once it well incorporated set aside.
In a medium blend 2/3 cup sugar with 1/2 lemon zest until the sugar turns an even color f yellow. Cream the sugar with 6 tablespoons of butter. Once it's lite and fluffy, beat in 2 eggs, and 1 teaspoon vanilla. When the batter become smooth, add in some of the 2 cups of flour, and some of the 1/2 cup buttermilk. Beat until slightly incorporated before add in some more flour, 2 teaspoons baking powder, 1/2 teaspoon baking soda, 1/4 teaspoon salt, 1/4 teaspoon cinnamon ,1/8 teaspoon nutmeg and the remaining buttermilk. Beat until everything is slightly incorporated before add the remaining flour. Beat until you have a smooth batter. Scoop half of the batter into the individual cake pans. Top with half pint of blueberries, and press them into the batter. Place the remaining batter on top and add the remaining blueberries on top. Top with the crumb mixture and bake for 30 minutes. Allow to cool before packaging.