Brown the butter: Add the butter to a pan on the stovetop on medium heat, and let it melt. Continue to cook the butter until it is golden brown. The butter will start to get foamy, and you will have toasted milk solids at the bottom. Pour into a heat-proof bowl or jar to cool slightly before using.
Once ready to bake the cookies, preheat the oven to 325ºF, and prepare a baking sheet with parchment paper or silicone lining.
In a large bowl, add the ripe bananas and mash them completely. Add in brown butter, brown and white sugars, and vanilla. Mix until fluffy.
Add in the dry ingredients (flour, salt, baking soda and cinnamon) and mix well until all the dry mixture is combined with the wet ingredients just until combined. Don’t overmix.
Fold in chocolate chips and nuts to mix.
Drop spoonfuls of the cookie batter onto the prepared cookie sheet. The cookie dough balls should be at least 1.5 inches apart.
Bake at 325ºF for 12-18 mins until the edges start to brown
Cool slightly before enjoying.