1. Prepare your flax egg, and melt the vegan butter or coconut oil. Set these items aside.
2. In a large mixing bowl, combine the oats and nondairy milk. Let sit 25 minutes to soften.
3. Preheat the oven to 400 degrees Fahrenheit (about 200 degrees Celsius). Grease or line a muffin pan, or use a silicone pan.
4. In a new mixing bowl, stir the flours, baking powder, cinnamon, salt, and baking soda until well combined.
5. Whisk maple syrup, butter, flax egg, and vanilla extract into the milk oat mixture. Then combine with the dry ingredients and stir until just evenly mixed.
6. Very gently fold in the blueberries.
7. Divide muffin batter evenly into the prepared tins. Sprinkle each top with about a teaspoon of cane sugar.
8. Bake 7 minutes on the center rack of the oven. Then lower the temperature to 350 degrees Fahrenheit (176 degrees Celsius), without ever opening the oven door. Continue to cook for another 22 minutes.
9. When time is up, test for doneness by inserting a toothpick into the center of a muffin. The muffins are done if the toothpick comes out mostly clean.
10. Let cool on the counter before removing from the muffin tins.
11. If you can wait, both the flavor and texture of these vegan blueberry muffins are even better the next day!
12. Store leftovers loosely covered on the counter overnight or covered and refrigerated for up to five days. Or freeze leftover muffins in an airtight container for up to three months.