Start by combining graham cracker crumbs, brown sugar, zest and melted butter in a large bowl until it sticks together like wet sand.
Spray the bottom of a 9-inch pie plate with your preferred baking spray and pack your crust into the pie plate until it’s densely and compactly situated. Bake for about 10-minutes or until it’s looking golden and the smells start wafting. Set aside crust to cool, but don't turn off our oven.
For your filling, whisk together 4 egg yolks for about two minutes. Add your lime zest and continue whisking until your mixture is a pale green.
Whisk in your lime juice and condensed milk until your filling starts to thicken. Let rest for at least 20-minutes at room temperature, giving the filling adequate time to firm up. Pour filling into the cooled pie crust and return it to your 350 degree oven for 15-20 minutes or until the center of your pie is firm.
Let your pie rest until it reaches room temperature and then place in the fridge to chill (can be made up to a day in advance).
Slice & serve chilled with a dollop of whipped cream and a slice of lime!