Very Berry Pancakes with Mixed Berries and Maple-Yogurt Topping

2 teaspoons baking powder

1 teaspoon baking soda

2 tablespoons sugar

1/2 teaspoon salt

2 eggs, beaten

2 1/4 cups shaken buttermilk, plus more for loosening batter if necessary

2 tablespoons butter, melted and slightly cooled

1/2 cup frozen or fresh blueberries Melted butter for cooking pancakes MIXED BERRIES:

2 cups sliced berries (strawberries, raspberries, blackberries, blueberries)

1 tablespoon lemon juice

2 teaspoons sugar MAPLE-YOGURT TOPPING:

2 cups plain yogurt

1/4 cup maple syrup finely grated zest of

1 lemon