Preheat oven to 350 degrees. Line an 8x8 inch pan with parchment paper or aluminum foil for easy removal. In a medium sized bowl, add flour, brown sugar, and melted butter and mix together until incorporated. Press down in your 8x8 inch pan and bake for 10 minutes or until lightly brown.
To make the coconut lime layer: In a medium sized bowl, add egg yolks, sweetened condensed milk. lime juice, and zest of one lime. Whisk together until smooth and pour over crust. Top with coconut. Bake for 15 minutes or until set.
Let cool completely before serving. I like to chill mine in the fridge before serving.