Preheat the oven to 375°F (190°C). Line a 12-cup muffin tin with paper liners or grease it lightly.

In a medium bowl, mix the oats and milk. Let them sit for 10 minutes.

In a large bowl, whisk together the flour, brown sugar, granulated sugar, baking powder, baking soda, cinnamon, nutmeg, and salt.

In another bowl, whisk the applesauce, melted butter, eggs, and vanilla until smooth.

Pour the wet mixture into the dry ingredients, add the soaked oats, and stir until just combined.

Fold in any optional nuts or dried fruit.

Divide the batter evenly among the muffin cups, filling each about three-quarters full.

If desired, sprinkle with additional toppings.

Bake for 18 to 22 minutes, until the tops are golden.

Cool in the pan for 5 minutes, then transfer to a wire rack.