1. Prepare the Oven and Muffin Tin: Getting Ready to Bake

1. Preheat Oven: Preheat your oven to 400°F (200°C).
2. Line Muffin Tin: Line a standard 12-cup muffin tin with paper liners.

2. Make the Streusel Topping: A Buttery, Crunchy Layer

1. Combine Dry Ingredients: In a small bowl, whisk together 1 cup of all-purpose flour, ⅔ cup of granulated sugar, and 1 teaspoon of cinnamon.
2. Add Melted Butter: Pour the melted salted butter (1 stick or ½ cup) over the dry ingredients.
3. Mix with Fork: Stir the mixture with a fork until it resembles coarse crumbs. You should have pea-sized clumps of butter mixed throughout.
4. Refrigerate: Place the streusel topping in the refrigerator to chill while you prepare the muffin batter. This will help it maintain its crumbly texture during baking.

3. Prepare the Muffin Batter: Combining Wet and Dry Ingredients

1. Whisk Dry Ingredients: In a large bowl, whisk together 2 cups of all-purpose flour, 3 teaspoons of baking powder, and ½ teaspoon of salt. Set aside.
2. Combine Wet Ingredients: In a separate medium bowl, whisk together 2 large eggs (or 3 small eggs) and 1 cup of granulated sugar until well combined.
3. Add Yogurt, Oil, and Vanilla: Whisk in 1 cup of yogurt, ½ cup of canola oil, and 1 teaspoon of vanilla extract until the mixture is smooth and pale yellow.

4. Gradually Add Dry Ingredients to Wet: Creating a Tender Crumb

1. Combine: Add the dry ingredients to the wet ingredients in two or three additions, mixing gently with a rubber spatula after each addition until just combined.
   • Tip: Be careful not to overmix the batter, as this can lead to tough muffins.

5. Prepare and Add Blueberries: Preventing Sinking

1. Toss Blueberries with Flour: In a small bowl, sprinkle 1 cup of the blueberries with 1-2 tablespoons of flour and toss gently until each blueberry is lightly coated. This will help prevent them from sinking to the bottom of the muffins during baking.
2. Fold in Blueberries: Gently fold the floured blueberries into the muffin batter using a rubber spatula, being careful not to overmix or crush the berries.

6. Assemble and Bake the Muffins: Achieving Golden-Brown Perfection

1. Fill Muffin Cups: Spoon the batter into the prepared muffin liners, filling each cup about ⅔ full.
2. Add Remaining Blueberries: Divide the remaining 1 ⅓ cups of blueberries among the muffin cups, placing them on top of the batter.
3. Top with Streusel: Remove the chilled streusel topping from the refrigerator. Generously top each muffin with the streusel crumbs, gently pressing them into the batter.
4. Bake: Place the muffin tin in the preheated oven and immediately reduce the oven temperature to 375°F (190°C). Bake for 18-20 minutes.
   • Check for Doneness: The muffins are done when a toothpick inserted into the center comes out clean, or with just a few moist crumbs attached. The tops should be golden brown and the streusel topping should be crispy.
5. Cool: Remove the muffin tin from the oven and let the muffins cool in the tin for about 5 minutes before transferring them to a wire rack to cool completely.

7. Serve and Enjoy: Savoring Your Delicious Creation

1. Serve Warm or Cool: These muffins are delicious served warm or at room temperature.