Preheat oven to 375℉. In a medium bowl, whisk together the flour, oats, baking powder, baking soda, cinnamon, and salt. Set aside.
In a separate medium bowl, whisk together the eggs and brown sugar. Next, add the coconut oil and vanilla, and whisk to combine. Add the dry ingredients to the wet, and fold with a rubber spatula until combined. Fold in the chocolate chips.
Chill cookie dough for 30 minutes. (Don't skip this!) While dough is chilling, make the frozen yogurt. Add yogurt, berries, honey, and vanilla to a food processor or blender and pulse until berries are all chopped up and mixture is combined. You don't want any large chunks.
Line a 8x8 baking pan or square dish with parchment and pour yogurt mixture into the pan. Freeze for one hour. In the meantime, once dough is done chilling, scoop cookie dough into a little smaller than golf ball sized balls onto a parchment lined baking sheet. You'll probably need to do this in 2 batches. You should get about 24 cookies.
Spoon a tablespoon or so of yogurt onto a cookie half, and top with another cookie. Place on a parchment lined sheet or in a pan that will fit in the freezer. Repeat until you have 12 cookie sandwiches! Freeze sandwiches for 1 hour, and enjoy! (You'll have leftover Greek yogurt too!).
*Nutrition information is calculated using about half of the frozen yogurt.