Buttermilk Berry Muffins

INGREDIENTS

• 1 1/4 cups / 5 1/2 oz / 160 g whole wheat pastry flour
• 2 1/4 cups / 10 1/2 oz / 295 g unbleached all-purpose flour
• 1/2 cup / 3 1/2 oz / 100 g firmly packed brown sugar
• 3/4 teaspoon fine grain sea salt
• 1/2 teaspoon baking soda
• 2 teaspoons baking powder
• 5 1/2 oz mashed, ripe banana (~2 med.)
• 240 ml buttermilk
• 3 large eggs
• 1 teaspoon vanilla extract
• 1/2 cup / 4 oz / 115 g unsalted butter, barely melted
• 1 cup / 4.5 oz / 125 g berries, plus more for topping
• rose cinnamon sugar*