1. In the bowl of an electric mixer, beat margarine and sugars. Mixing on low speed, add eggs, peanut butter, and vanilla.
2. In a small bowl, combine flour and baking powder. Add to the mixing bowl. Mix in the oats. Remove the bowl from the mixer and refrigerate the dough for 30 minutes.
3. Preheat oven to 350 degrees Fahrenheit. Line a baking sheet with Gefen Parchment Paper.
4. Form two-tablespoon-sized balls and flatten slightly. Place on baking sheet and press some blueberries into each cookie. Bake for 10–12 minutes, until slightly golden.