Step 1: Preheat your oven to 350°F (175°C). Grease your 9x13-inch baking pan with butter or non-stick spray.
Step 2: In a mixing bowl, whisk together 2 ½ cups of all-purpose flour, 2 teaspoons of baking powder, ¼ teaspoon of cinnamon, and ¼ teaspoon of salt. Set aside.
Step 3: In a small saucepan, melt ½ cup of unsalted butter until golden brown. Stir occasionally to prevent burning. Once browned, let it cool.
Step 4: In a large mixing bowl, combine the cooled brown butter, ½ cup of brown sugar, and ¼ cup of granulated sugar. Beat until well combined. Add 2 egg yolks, 2 teaspoons of vanilla extract, and 4 mashed bananas. Mix until smooth.
Step 5: Gradually add the flour mixture to the wet ingredients, alternating with ⅔ cup of whole, 2%, soy or almond milk. Mix until just combined.
Step 6: In a separate bowl, beat the 2 egg whites until stiff peaks form. Gently fold the egg whites into the cake batter using a rubber spatula, being careful not to deflate the mixture.
Step 7: Pour the batter into the greased baking pan and bake for 25-30 minutes or until a toothpick inserted in the center comes out clean. Allow the cake to cool completely in the pan on a wire rack.
Step 8: In a bowl, whisk together ½ cup of sweetened condensed milk, ½ cup of evaporated milk, and ½ cup of light coconut milk. Once the cake is cool, poke holes all over the surface with a fork and pour the tres leches mixture evenly over the cake. Let it soak for at least 30 minutes.
Step 9: In a large bowl, beat 1 ½ cups of cold heavy whipping cream and 2 tablespoons of powdered sugar until soft peaks form. Spread the whipped cream over the soaked cake.
Step 10: In a skillet, melt 3 tablespoons of unsalted butter over medium heat. Add 3 tablespoons of brown sugar, ¼ teaspoon of cinnamon, and a pinch of salt. Stir until the sugar dissolves, then add the sliced bananas. Cook for about 2-3 minutes until caramelized.
Step 11: Top the whipped cream layer with the caramelized bananas. Slice the cake into squares and serve chilled or at room temperature. Enjoy!