Preheat your oven to 350°F (175°C). In a skillet over medium heat, toast 1 cup of coconut flakes until golden brown, stirring frequently for about 5–7 minutes.

In a mixing bowl, combine 1 ½ cups crushed graham crackers, ½ cup melted butter, ¼ cup brown sugar, and the toasted coconut. Press the mixture firmly into the bottom of a 9x9-inch baking dish.

Bake for 10 minutes or until set, then let it cool before adding the filling.

In a separate mixing bowl, whisk together 4 large egg yolks until smooth, then gradually add 1 can (14 oz) sweetened condensed milk and ½ cup freshly squeezed key lime juice. Continue whisking until well combined and the mixture thickens slightly, about 2-3 minutes.

Pour the lime filling over the cooled crust, smoothing the top with a spatula.

Bake in the preheated oven at 350°F (175°C) for 15-20 minutes.

Remove from the oven and let it cool at room temperature for about 30 minutes.

Once the bars have cooled, cover the baking dish with plastic wrap and place it in the refrigerator. Chill for at least 3 hours, preferably overnight.

After chilling, use a sharp knife to slice the bars into squares.

Serve the chilled creamy key lime pie bars with a dollop of whipped cream on top and a sprinkle of lime zest.