Banana Brownies with Walnuts

0 Pre-heat oven and prepare the brownie pan. Pre-heat your oven to 350F. Grease an 8×8 brownie pan and then line it with parchment paper. I like to cut a sheet of parchment in half and line the pan as shown below.
1 Mix dry ingredients. In a medium mixing bowl, combine sifted flour, sifted cocoa powder, espresso powder and salt. Mix together with a fork or whisk to fully incorporate.
2 Heat butter & chocolate chips. In a small saucepan over medium low heat, melt butter + chocolate chips stirring gently with a silicone spatula. As the butter starts melting, turn the heat to low and continue to stir until the chocolate is melted, then transfer to a large mixing bowl. Be sure not to let the mixture boil or burn.
3 Prepare the mashed banana. In a medium mixing bowl, add overripe bananas and mash using a fork. Alternatively, you can also make the banana puree in a food processor to save time.
4 Beat in banana, vanilla, eggs & sugars. In the same large mixing bowl you just added the butter and chocolate mixture, add the mashed banana, vanilla extract, then the monk fruit sugar and the coconut sugar, whisking to combine. Then add each egg one by one, whisking lightly between each egg then whisking one last time a bit more vigorously once all eggs have been added to fully incorporate, about 30 more seconds.
5 Mix the batter. Add flour mixture to wet ingredients, folding in gently using a silicone spatula until all dry ingredients are fully combined and no clumps or traces of flour remain. Add extra chocolate chips and fold into batter along with walnuts if using. You can also add slices of banana to the top of the batter if you're a true banana lover and have an extra banana around.
6 Bake & chill. Bake the brownies for 35-45 minutes until a toothpick comes out of the center clean and there is no wobble in the batter if you jiggle the pan. Allow brownies to cool at room temperature, then chill for at least 2 hours before serving. Chilling the brownies helps them set and the texture becomes extra fudgy.