• Preheat oven to 350°F. Line muffin tins with paper liners or spray with cooking spray. Set aside.
• Start by making the crumble topping. Then it will be ready to top as soon as you fold in the blueberries, so they don't turn the batter too blue/purple.

Crumb Topping

• With a fork, mix together sugars, flour, cinnamon, and salt.
• Pour melted butter into dry mixture and use fork to mix together, allowing clumps to form. The larger the clumps, the larger the crumbs on top of the muffins will be. Set aside once mixed.

Muffins

• Mix dry ingredients together and set aside.
• In a large bowl combine sugar, butter, eggs, and vanilla. Mix well.
• Once incorporated, mix in sour cream/or yogurt and milk.
• Then slowly add dry mixture to wet, mixing well. Use a whisk if needed to get out any clumps.
• In a separate bowl, mix blueberries with ¼ cup of flour. Just sprinkle the flour lightly over the blueberries, and turn gently with a spoon, so you don't crush the blueberries. Mixing the flour with the blueberries will keep them from all sinking to the bottom of your muffins.
• Once all blueberries are coated, carefully fold blueberries into muffin mixture.
• Once mixed, use a large kitchen scoop or spoon to spoon batter into prepared muffin tins. Fill about ¾ full.
• Sprinkle 1-2 tablespoons of crumb topping over each muffin. Bake in preheated oven for 20-25 minutes until tops spring back and/or until a toothpick inserted comes out clean.
• Let muffins rest in tin for 10-15 minutes after you remove them from the oven. The berries will be very hot and this will give the muffins time to rest.
• Once slightly cooled, remove from tin and enjoy!

Optional glaze

• If you’d like to add a glaze, add powdered sugar to a small bowl. Slowly add milk, 1 tablespoon at a time, while constantly whisking until it drizzles off the whisk. Don’t make it too thin or it will melt into the muffins.
• Using a spoon, drizzle glaze over muffins and let set . Enjoy!