Place a medium pot over medium high heat and drop in the butter. Allow it to melt, bubble, and then froth. After about 6-8 minutes the colour will start to darken and you will get a lovely nutty aroma. Remove from heat and pour into large bowl. You just made browned butter!
Into the bowl add in the brown sugar, white sugar, banana, yogurt, and vanilla. Stir quickly to help the sugar dissolve into the butter. Don't rush this mixing part.
Once mixed add in the dry ingredients. Flour, oats, cinnamon, salt, baking powder, baking soda, mini chocolate chips, chocolate chunks. Mix and then place the bowl into the fridge for freezer for 30-40 minutes. DO NOT SKIP THIS STEP!
Preheat oven to 400F and line a large cookie sheet with parchment paper.
Using an ice cream scoop scoop out the cookie dough and lay cookie ball on the baking sheet being sure to give 2 inches between cookies.
Bake cookies for 14-17 minutes. You want the sides to be golden brown.
Once baking is done, remove from oven but leave cookies on baking sheet for another 5-10 minutes. This is part of the baking process and cannot be skipped. Ideally you then place the cookies on a cooling wrap for another 5 minutes.
