I don't have a cookie sheet right now, but I do have a small roasting pan (it's like 6 inches by 9 inches), so I tried making squares out of it and baking it a little longer - it came out soft in the middle, but I could still cut up the rest of it to make it presentable... and someone else in the house didn't mind eating the messed up part!
Banana Oatmeal Cookies
1 cup all purpose flour
1/2 tsp baking powder
1/2 tsp baking soda
1/4 tsp salt
2 tbsp butter, very soft
1/2 cup sugar
1/2 cup brown sugar
1/4 cup mashed banana (1 small/medium)
1 tsp vanilla extract
1 1/2 cups oats
1 cup chocolate chips
Preheat oven to 350F and line a baking sheet with parchment paper.
In a small bowl, whisk together flour, baking powder, baking sodaand salt.
In a large bowl, cream together the butter and the sugars. Beat in egg and banana, followed by the vanilla extract. Gradually, on low speed or by hand, add in the flour mixture. Stir in the oats (either whole rolled oats or "quick cooking") and chocolate chips.
Drop dough by tablespoonfuls onto prepared baking sheet.
Bake for 11-14 minutes at 350F, until set and lightly browned.
Let cookies cool for about 5 minutes on the pan before transfering them to a wire rack to cool completely.
Makes 2 dozen cookies.