Preheat the oven to 350˚F. Spray a 9x5 inch loaf pan with cooking spray then line the inside with parchment paper.
In a bowl, whisk the flour, baking soda, baking powder, cinnamon, and kosher salt together. Add in the chopped toffee and toss it in the flour mixture.
Add the eggs, brown sugar, and granulated sugar to a large bowl. Whisk until combined and the mixture turns into a light brown color. Mix in the bananas, vanilla extract, vegetable oil, and milk. Whisk until well combined. Add the dry ingredients to the bowl of wet ingredient and gently fold the batter together until everything is well incorporated.
Pour half of the batter into the loaf pan. Drizzle 1 tablespoon of the salted caramel over top then sprinkle on 1/4 teaspoon of the flaky salt. Swirl the caramel and flaky salt into the batter with a knife or chopstick. Add the remaining half of the batter to the pan and swirl in the remaining salted caramel and flaky salt.
Place the pan on top of a baking sheet and bake it in the oven for for 60-70 minutes until a toothpick inserted comes out clean. Let it cool in the pan for 30 minutes then transfer it out of the pan onto a wire rack to cool completely. When completely cooled, spread more salted caramel on top. Sprinkle with more toffee and flakey salt. Enjoy!