Preheat oven to 350 degrees. Line a muffin pan with paper muffin cups.
In a large mixer, cream the butter and the sugar. Beat in the eggs, then the flours and dry all ingredients (except powdered sugar).
Add the milk, lemon zest, lemon juice and vanilla. Mix until combined. Stir in by hand 1 cup of fresh or frozen blackberries (or blueberries).
Spoon batter into prepared muffin papers. Bake for 15-20 minutes.