Combine the flour, oats, baking powder, baking soda, salt and cinnamon in a large bowl.
Cream the butter and sugar together until smooth, then add the yogurt, eggs, vanilla and mashed bananas. Beat until smooth with an electric mixer on medium speed, about 1-1/2 minutes.
Add the wet ingredients to the dry and combine thoroughly. Fold in the chocolate chips.
Drop by rounded tablespoonfuls onto parchment-lined cookie sheets, about 2-inches apart. Bake until firm to the touch and very lightly browned, 12 to 15 minutes. Cool on wire racks.
Tips for Making This Recipe
Store cookies in containers with tight-fitting lids and place wax or parchment paper between the layers to keep them from sticking. Cookies can be stored at room temperature for up to 3 days, in the refrigerator for up to a week, and in the freezer for up to three months.