Mixed Berry Muffins

0 Preheat the oven to 400°F. Line a muffin tin with baking cups. Spritz the cups with nonstick baking spray, if desired, and set aside.
1 Toss the blueberries, raspberries and blackberries in the extra 1 tablespoon of flour. Set aside.
2 Measure the rest of the flour (2 cups), baking powder and kosher salt into a medium bowl. Whisk to combine. Set aside.
3 Combine the sugar, sour cream and vegetable oil in a large bowl. Mix together until combined and smooth with a rubber spatula.
9 Add the lemon zest, eggs and vanilla extract. Stir to combine.
4 Pour in the milk, and stir until just combined.
5 Sprinkle the dry ingredients on top of the wet, and stir until the muffin batter comes together. Do not overmix!
6 Gently fold in berries to the batter until they are scattered throughout. Be gentle, as the berries can fall apart if you are too rough with them.
7 Measure 3 tablespoons of the batter into each of the prepared muffin tins. 
10 Sprinkle raw sugar over the tops of the muffins, and transfer to the preheated oven. 
11 Bake for 25-28 minutes, or until golden brown and cooked through to where an inserted toothpick comes out clean.
8 Let the muffins cool for 15-20 minutes, then enjoy!