Preheat the oven to 350 degrees Fahrenheit (180 degrees Celsius). Line the mini muffin pan with liners and set aside.
Combine 2 tablespoon flour, 2 tablespoon sugar, and 1 tablespoon melted butter in a small bowl until a crumble forms. Set it in the freezer while you make the muffin batter.
Whisk together the flour, baking powder, cinnamon, and salt in a medium mixing bowl and set aside.
1 ¼ cup all purpose flour, 1 ½ teaspoons baking powder, ½ teaspoon cinnamon, ¼ teaspoon salt
In a separate large mixing bowl, whisk the granulated sugar, brown sugar, melted butter, oil, egg, and vanilla until well combined.
½ cup granulated sugar, 2 tablespoons brown sugar, 2 tablespoons unsalted butter, 2 tablespoons vegetable oil, 1 large egg, ½ teaspoon vanilla extract
Add the Greek yogurt and buttermilk, whisking until smooth.
¼ cup full fat Greek yogurt, ¼ cup buttermilk
Using a rubber spatula, fold the dry ingredients into the wet ingredients until a few dry streaks of flour are left.
In a small bowl, coat the blueberries in about 2 teaspoons of flour. Fold the blueberries into the muffin batter until no dry streaks remain.
1 cup frozen blueberries
Using a small cookie scoop, fill each liner ¾ full of batter. Sprinkle a little of the streusel and coarse sugar on top of each one.
Bake on the middle rack for 12-15 minutes or until a toothpick inserted in the center comes out clean. Transfer to a wire rack when the muffins are cool to the touch.
Video
Notes
Use room temperature egg, yogurt, and buttermilk.Measure the flour correctly in grams with a food scale. See the metric tab above. If measuring in cups, use the spoon and sweep method.Storage: Store the muffins in an airtight container at room temperature for 3-4 days or in the freezer for up to 3 months.Nutrition: The provided nutritional information is an estimate, the calorie accuracy is not guaranteed.