¾ cup all-purpose flour
¼ teaspoon baking soda
1 teaspoon baking powder
⅛ teaspoon salt
¼ cup sugar
¼ cup vanilla yogurt
2 tablespoons butter, melted
1 egg, lightly beaten
½ teaspoon vanilla extract
½ cup fresh blackberries
! Topping
1 teaspoon fine lemon zest
1 tablespoon granulated sugar