Line a baking sheet or pizza pan with parchment paper (for easy clean-up).
Mix everything together.
Scoop 18 medium-sized cookies onto the baking sheet. A cookie dough scoop with a sweep or wiper works well here.
Bake for 15 minutes.
Check the cookies by breaking one open. If it's not baked through, bake for a few more minutes. The larger the cookies, the longer the bake time.
Notes
This recipe doesn't work well with old-fashioned oats, unfortunately. The quick oats are more processed, which makes them able to absorb moisture and act kind of like a flour.
Feel free to use fresh berries of any kind. This recipe also works well with sliced banana, chopped nuts, and dark chocolate chips.