Combine oats, brown sugar, flour, coconut, baking powder, and salt in a large bowl.
Add soften butter, milk, and vanilla. Mix together with a wooden spoon (or your hands) until well combined.
Use a 2-tablespoon cookie scoop or spoons to form cookies. Roll dough into balls and flatten with a fork dipped in a little additional milk.
Bake on parchment covered baking sheet at 375°F [190°C] for 10-12 minutes.
Notes
Baked oatmeal cookies freeze very well. Simply place cooled cookies on a baking sheet and freeze for about on hour. Then place the cookies in a freezer safe container, separating any layers with waxed or parchment paper.Cookies will stay freshly frozen about 2 months; after that, it depends on your freezer and how often it gets opened.