Combine milk and oats. Set aside for 10 minutes so the oats soak up some moisture.

Preheat oven to 425°F.

Line the desired size muffin pan with muffin liners.

Whisk the flour, baking powder, baking soda, cinnamon, and salt together in a large bowl until combined. Add blueberries and stir.

In a separate bowl, whisk together applesauce, egg, and vanilla extract.

Mix the dry and wet mixtures together and add the soaked oats. Mix.

Scoop the batter into the muffin tray, filling them all the way to the top.

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.

Allow the muffins to cool for 5 minutes in the muffin pan, then transfer to a wire rack to continue cooling.