Preheat the oven to 375 F (190 C) for at least 30 minutes before baking. Line (2) 12 ct. muffin pans with cupcake liners.
In a mixing bowl, whisk the flour, baking powder, cinnamon and salt together until well combined.
2 cups (240 g) all purpose flour, 1 tablespoon baking powder, ½ teaspoon salt, ½ teaspoon ground cinnamon
In another large mixing bowl whisk the oil, sugar, eggs, milk, sour cream and vanilla extract until well combined. Stir the dry ingredients into the wet until just combined. Do not overmix. Stir the flour coated blackberries into the muffin batter.
¾ cup (150 g) granulated sugar, ½ cup (120 ml) oil, 2 large eggs, room temperature, ½ cup (120 g) sour cream, room temperature, ½ cup (120 ml) milk, room temperature, 1 teaspoon vanilla extract , 2 cups blackberries
Use a 3 tablespoon sized cookie scoop to scoop the blackberry sour cream muffin batter into each of the muffin liners, alternating every other cup. Top the muffins with sugar if you like. Top the muffins with sugar if you like.
2 tablespoons (25 g) granulated sugar for topping, optional
Bake the muffins at 375 (190 C) for 18 - 22 minutes. The muffins are done when a toothpick inserted into the center comes about with a few moist crumbs or when a finger pressed gently into the center of the muffins quickly bounces back. Cool the fluffy blackberry muffins in the muffin pan for 5 - 10 minutes. Carefully remove the muffins to cool to room temperature and enjoy.