
Preheat your oven to 375F (190C) and prepare a muffin pan by spraying the cavities with cooking spray or lining them with parchment paper liners. Set aside.
In a large mixing bowl, combine the flour, oats, flaxseed, cinnamon, baking powder, baking soda, and salt. Set aside.
In a separate bowl, lightly beat the egg just to break it up. Whisk in the yogurt, maple syrup, almond milk, oil, and vanilla, mixing until well combined.
Add the wet ingredients to the dry ingredients, mixing gently until just combined. Toss the blueberries in 1 Tbsp (7.5 g) of flour to prevent them from bleeding or sinking to the bottom of the muffins, and gently fold them into the batter.
Divide the batter evenly among the 12 muffin cups, filling almost to the top.
Bake for 20 – 22 minutes, or until the tops of the muffins begin to turn golden and a toothpick inserted into the centre comes out clean. Allow the muffins to cool in the pan for ~5 minutes before transferring them to a wire rack to cool completely. Store in an airtight container at room temperature for up to 5 days, or freeze for up to 3 months.