An easy no-bake oatmeal cookie recipe is Quaker's 3-Minute No-Bake Cookies. Made using only four ingredients besides oatmeal, this recipe yields about three dozen cookies.
To make Quaker's 3-Minute No-Bake Cookies, start by mixing together 3 cups sugar, 8 tablespoons butter, 1/2 cup low-fat milk and 1/2 cup baking cocoa in a large saucepan. Bring the mixture to a boil over medium heat while stirring. Boil for 3 minutes, then remove from heat. Add in 3 cups quick oats, then spoon tablespoon-size amounts onto waxed paper. Let the cookies sit until firm.
For this recipe, it is possible to substitute old fashioned oats for quick cooking oats. In order to do so, the butter mixture should cool in the saucepan for five minutes before adding the oats.
To make chocolate peanut butter no-bake cookies, mix together 2 cups sugar, 4 tablespoons cocoa, a stick of butter and 1/4 cup milk in a heavy saucepan. Bring the mixture to a boil, then allow the mixture to boil for one minute. Stir in 1 cup peanut butter, 1 tablespoon vanilla and 3 cups oatmeal. Spoon the mixture onto wax paper in teaspoon-sized balls. Allow the cookies to sit on the waxed paper until cooled and firm.