Preheat oven to 350° Fahrenheit.
Crust:
Combine graham crackers, sugar and butter. Press crust down on pie dish using the bottom of a dry measuring cup or a drinking glass, and up the sides of a 9 x 1½ -inch pie pan. Bake for 8 minutes, until just slightly browned. Set aside and let the crust cool for 5 minutes.
Filling:
In a large bowl, whisk together the sweetened condensed milk, lime juice, and egg yolks. Pour the thick mixture into the warm graham cracker crust. Bake for 15 minutes, until the filling is almost set (but still a little wobbly in the center). Let cool at room temperature for 1 hour. Refrigerate pie for a minimum 3-4 hours.
Topping:
In a small bowl, combine the sour cream and powdered sugar; whisk until smooth and creamy. Right before serving pie, spread cream on top of filling and garnish with a fresh lime slice. Enjoy!
