Grease a 24-cup mini muffin pan with nonstick spray or oil.
In a medium bowl, stir together the 1 ¼ cups oat flour, ½ cup granulated sugar, 1 teaspoon baking powder, ½ teaspoon baking soda, ½ teaspoon ground cinnamon, and ¼ teaspoon salt.
In another bowl, stir together the ¾ cup plain Greek yogurt, ¼ cup oil, and 2 large eggs.
Gently stir the yogurt mixture into the flour mixture, then fold in the ½ cup blueberries.
Preheat the oven to 375℉. Divide batter among the prepared muffin tin, filling about to the edge. Rest the batter while the oven heats.
Place in the oven and bake for 12-14 minutes, or until the edges are lightly golden brown and a tester inserted into the center comes out cleanly.
Remove from oven, and let cool in the pan for 2 minutes. Run a paring knife around the edges to loosen, if needed, then carefully transfer muffins to a wire rack to cool fully.
Notes
What kind of blueberries? You can use fresh or frozen berries, and if you can get some smaller wild blueberries, they are also perfect for smaller pops of fruit flavor.
Fold in the berries gently. Especially important if using frozen berries! Gently fold in the berries so that they don't turn the batter blue (unless you want this so in that case - go ahead!).
Grease the pan well. I advise using non-stick spray or well-greasing the muffin tin so that the muffins release easily.
Don't overbake. This can lead to sticking or dryness, so check at 15 minutes for doneness.
Make regular-sized. Feel free to make these muffins in a regular-sized muffin tin for larger muffins. Adjust the baking time if needed - they may need about 5 additional minutes.
Add lemon zest. I always love the combination of lemon and blueberry! Stir in the zest of 1 lemon for a bit of bright, citrusy flavor.