Heat oven to 350 F. Line cookie sheets with parchment paper; set aside.
In large bowl, stir oats, flour, brown sugar, baking powder and salt. In medium bowl, stir butter, milk, egg and vanilla until well mixed; add to oat mixture. Stir until combined and evenly moistened.
Drop 1/4 cup dough onto prepared cookie sheets. Slightly flatten dough with hand.
Bake 15-17 minutes, or until lightly browned, firm to touch and baked through. Move to wire rack to cool.
Variations:
Add maple syrup and crumbled bacon; sliced almonds, dried cherries and almond extract; semisweet chocolate chips and banana pieces; or peanuts and peanut butter.