This is one of the best ways to use up a bunch of bananas that are about to go bad. You will want to cut yourself a little piece right from the oven, but resist the temptation. Let the bars cool in the sheet pan until they reach room temperature. You can have a slice at this point, but these are best when you allow them to rest in the refrigerator overnight. It’s an exercise in patience but so worth it. —Carlos C. Olaechea
Lightly grease a quarter sheet pan and cover the bottom with parchment paper. Set aside.
Place the flour, cocoa powder, sugar, and salt into a food processor. Cover and pulse a few times until the dry ingredients are well-combined.
Add the butter all at once and pulse until the butter and the dry ingredients form a sandy consistency. Add the nuts and pulse again until everything forms a soft ball. Turn out the mixture onto the prepared sheet pan and smooth out with your fingers, making the dough reach the sides and corners of the sheet pan.
Place the sheet pan in the freezer. Meanwhile, preheat the oven to 350°F. Once the oven comes to temperature, remove the sheet pan from the freezer and prick the dough all over with a fork. Place on the middle rack of the oven and bake for 15 minutes.
Remove the sheet pan from the oven and place on a rack to cool to room temperature. It will seem too soft to support the bananas and condensed milk, but just let it rest. It will harden as it cools. Meanwhile, raise the oven temperature to 375°F.
When the cookie base has cooled completely, place a layer of bananas on top of it, slightly overlapping each slice of banana. Now evenly pour the entire can of condensed milk over the bananas. You may use a flexible spatula to evenly distribute it, but don’t worry too much about it. It will even out in the oven.
Bake on the middle rack for 20 minutes. Rotate the pan 180 degrees and bake for another 10 to 15 minutes or until the top of the bars is sticky and lightly golden brown. You will only see a film of white. If you see too much liquidy condensed milk, put it back in the oven and bake for another 5 to 10 minutes.
Let cool completely before slicing and serving, preferably overnight in the refrigerator.
I was born in Peru to a Limeño father and a Texan mother. We moved to Miami when I was five, and I grew up in the "Kendall-suyo" neighborhood—often called the 5th province of the Inca Empire because of its large Peruvian population. I've been writing about food since I was 11 years old, and in 2016 I received a master's degree in Gastronomy from Boston University. A travel columnist at Food52, I'm currently based in Hollywood, Florida—another vibrant Peruvian community—where I am a writer, culinary tour guide, and consultant.