In a medium bowl, combine milk and oats. Allow oats to soak in the milk for 20 minutes. After 20 minutes, if the oats have not soaked up much milk, stir and let the oats soak 10 more minutes.
Preheat oven to 425°F (218°C). Grease a 12-count muffin pan with nonstick spray or use cupcake liners.
In a large mixing bowl, whisk together the flour, baking powder, baking soda, cinnamon, and salt. Set aside.
In a medium mixing bowl, stir together melted butter, applesauce, honey, egg, and vanilla extract until combined. Pour the wet ingredients into the dry ingredients, stir a few times, then add the soaked oats (milk included) and raspberries. Gently, stir the batter untiil just combined.
Evenly divide the batter into the 12 muffin cups, filling them all the way to the top. Bake for 5 minutes at 425, then 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 cooking time is about 22-23 minutes. (For mini muffins, bake 11-13 minutes at 350°F (177°C) the entire cooking time.) Allow the muffins to cool for 5 minutes in the muffin pan, then transfer the muffins to a wire cooling rack to continue cooling.
Muffins keep well, covered, at room temperature for about 2 days. Store in the fridge for up to a week.