Combine graham cracker crumbs, butter, sugar, and salt in a bowl.
Mix well and press firmly into the bottom of a 10-inch tart pan with a removable bottom.
Bake crust in a 350 degree oven for 10-15 minutes.
Filling
While crust is baking prepare filling.
Whisk together egg yolks, lime juice, lime zest, and sweetened condensed milk in a large bowl. NOTE: if using regular lime juice instead of key lime juice, add lemon juice.
Whisk until smooth.
Pour into baked crust.
Finish
Bake in 350 degree oven for 19-25 minutes.
Center of filling should be set and jiggle a little.
Chill tart.
Serve with a side of sweetened vanilla whipped cream or top the tart with dollops of whipped cream.
Use zest from one lime to decorate the whipped cream.
Recipe Notes
You will need a 10" tart pan with a removable bottom. Serves 10