Combine milk and oats. Set aside for 20 minutes so the oats puff up and soak up some moisture. This is crucial to the recipe! (I usually melt the butter now so it has a few minutes to cool.) Don’t do this the night before as that’s too long for soaking. If you find the oats haven’t soaked up any moisture after 20 minutes, give it a stir and wait 10 more minutes.
Preheat oven to 425°F (218°C). Spray a 12-count muffin pan with nonstick spray or use cupcake liners.
Whisk the flour, baking powder, baking soda, cinnamon, and salt together in a large bowl until combined. Set aside. Whisk the melted butter, honey, egg, and vanilla extract together in a medium bowl until combined. Pour the wet ingredients into the dry ingredients, stir a few times, then add the soaked oats (milk included, do not drain) and blueberries. Fold everything together gently just until combined.
Spoon the batter into liners, filling them all the way to the top. Top with oats and a light sprinkle of coconut sugar, if desired. Bake for 5 minutes at 425 then, keeping the muffins in the oven, reduce the oven temperature to 350°F (177°C). Bake for an additional 16-17 minutes or until a toothpick inserted in the center comes out clean. The total time these muffins take in the oven is about 22-23 minutes, give or take. (For mini muffins, bake 11-13 minutes at 350°F (177°C).) Allow the muffins to cool for 5 minutes in the muffin pan, then transfer to a wire rack to continue cooling.
Muffins stay fresh covered at room temperature for a few days, then transfer to the fridge for up to 1 week.
Make Ahead Instructions: For longer storage, freeze muffins for up to 3 months. Allow to thaw overnight in the refrigerator, then bring to room temperature or warm up in the microwave if desired.
Milk: I tested the blueberry muffins with unsweetened almond milk, but any milk, dairy or nondairy, can work. If using frozen berries, see note below.
Oats: I recommend whole oats. Avoid steel cut oats, quick oats, and instant oats. Steel cut oats won’t absorb the milk and quick/instant are too thin and will dissolve in the batter as it cooks.
Flour: For best taste and texture, I recommend all-purpose flour. If you try whole wheat flour, let me know how they turn out!
Oil: You can use canola, vegetable, or melted coconut oil instead of the butter, but the flavor will change. I strongly recommend melted butter.
Sugar: You can use 1/2 cup maple syrup, coconut sugar, or packed light or dark brown sugar instead of honey.
Berries: If using frozen berries, do not thaw and reduce the milk down to 3/4 cup (180ml). Frozen berries give off so much moisture and the muffins taste a little too wet. Reducing the milk helps. No other changes to the recipe ingredients or instructions.
Why the Initial High Temperature? The hot burst of air will spring up the top of the muffin quickly, then the inside of the muffin can bake for the remainder of the time. This helps the muffins rise nice and tall.
Nutrition: Using SparkRecipes calculator and calculated using unsweetened almond milk these muffins come out to 205 calories, 9g fat, 28g carbs, 2g fiber, and 4g protein each.