Preheat oven to 375°F. Spray a regular muffin tin with floured baking spray; set pan aside.

Place the raspberries in a medium bowl, add 1 tablespoon flour and toss to coat; set aside.

In a large mixing bowl, sift together 2 cups flour, baking powder, cinnamon, and optional salt, set aside.

In a medium mixing bowl whisk together eggs, and sugar until combined. Mix in milk, sour cream, oil, and vanilla extract.

Fold wet ingredients into dry ingredients and mix everything together by hand. Don't overmix. If your batter is too thick, add a splash of milk to thin it.

Fold in the chocolate chips.

Gently fold in the raspberries.

Using a medium cookie scoop, fill each of cavity of the prepared muffin tin to about 3/4-full.

Bake for about 30 minutes, or until tops are domed, puffed, and a toothpick inserted in the center comes out clean.

Allow muffins to cool in pan for about 10 minutes before carefully removing.