Preheat the Oven: Preheat your oven to 375°F (190°C). Line a muffin tin with paper liners or grease the cups lightly with cooking spray.
Prepare the Crumb Topping: In a small bowl, combine the flour, sugar, melted butter, and cinnamon. Mix until crumbly and set aside.
Prepare the Muffin Batter: In a large mixing bowl, whisk together the Kodiak Cakes mix and flour. In a separate bowl, beat the eggs and sugar until well combined. Add the sour cream, melted butter, and vanilla extract, mixing until smooth.
Combine Wet and Dry Ingredients: Pour the wet ingredients into the dry ingredients and gently fold together until just combined. Be careful not to overmix.
Fold in Blueberries: In a separate bowl, toss the blueberries with 2 tablespoons of flour until coated. Gently fold the flour-coated blueberries into the muffin batter.
Fill Muffin Cups: Divide the batter evenly among the prepared muffin cups, filling each about two-thirds full.
Add Crumb Topping: Sprinkle the crumb topping evenly over the muffin batter in each cup and add a couple more blueberries on top of each muffin.
Bake: Place the muffin tin in the preheated oven and bake for 20-25 minutes, or until a toothpick inserted into the center of a muffin comes out clean.
Cool and Serve: Allow the muffins to cool in the pan for a few minutes before transferring them to a wire rack to cool completely. Serve warm or at room temperature, and enjoy!