Preheat oven to 425 degrees F (220 degrees C). Grease muffin cups or line with paper muffin liners.
In a small bowl, combine milk and oats; let soak for 15 minutes.
In a separate bowl, beat together egg and oil; stir in oatmeal mixture. In a third bowl, sift together flour, sugar, baking powder and salt. Stir flour mixture into wet ingredients, just until combined. Spoon batter into prepared muffin cups until cups are 2/3 full.
Bake in preheated oven for 20 to 25 minutes, until a toothpick inserted into the center of a muffin comes out clean.