Bisquick Blueberry Muffins Ready in 30 Min: Crispy

Instructions:

1. Preheat your oven to 400°F (200°C). Note: A hot oven is vital for that initial burst of steam that creates the dome. Line your 12 cup muffin tin with paper liners or grease them thoroughly.
2. In a medium bowl, whisk the 2/3 cup milk, 1/3 cup sugar, 1/4 cup sour cream, 1 egg, 2 tbsp oil, and 1 tsp vanilla. Whisk until the mixture is completely smooth and pale.
3. Place 2 cups of Bisquick mix in a separate large bowl. Make a well in the center and pour in the wet ingredients. Note: Mixing wet into dry prevents large flour clumps.
4. Use a spatula to fold the ingredients together just until no dry streaks remain. Stop as soon as the flour disappears. The batter should look lumpy. Gently fold in the 1 cup of fresh blueberries.
5. In a small bowl, combine the 1/2 cup Bisquick, 1/2 cup brown sugar, and 1/2 tsp cinnamon. Cut in the 1/4 cup cold butter using a fork or your fingers until it looks like coarse sand.
6. Divide the batter evenly among the 12 muffin cups. They should be about three quarters full. Generously sprinkle the streusel over the top of each muffin, pressing down very lightly so it sticks.
7. Slide the tin into the center rack. Bake for 20 minutes until the tops are golden and a toothpick comes out clean. You should see the berries starting to sizzle and release their juices.
8. Let the muffins sit in the tin for 5 minutes. Note: This allows the structure to set so they don't fall apart. Transfer them to a wire rack to finish cooling so the bottoms don't get soggy.