For the crust, preheat oven to 375 °F and set an oven rack in the middle position.
In a medium bowl, combine the graham cracker crumbs, brown sugar, and melted butter. Use your hands to mix until well combined. Using your fingers and the bottom of a glass, press the crumbs firmly into the bottom and up the sides of a 9 x 1 ½ inch (deep-dish) pie pan. The crust should be about ¼ inch thick.
Bake for 10 minutes, until just slightly browned. Let the crust cool on a wire rack.
Filling
For the filling, lower the oven temperature to 350 °F.
In a large bowl, whisk together the sweetened condensed milk, yogurt, lime zest, and lime juice. Pour the thick mixture into the warm graham cracker crust. Bake for 15 minutes, until the filling is almost set, it should wobble a bit. Let cool at room temperature for 30 minutes, then place in the refrigerator to chill thoroughly, about 3 hours.
Topping
For the topping, beat the heavy cream in a bowl of an electric mixer until soft peaks form. Add the powdered sugar and beat until medium peaks form. Top the pie with the whipped cream. Decorate with lime zest and lime slices. Store the pie in the refrigerator until ready to serve. Slice the pie into wedges, wiping your knife clean between slices, and serve cold.
This recipe was calculated using the exact brands and measurements I used to make this recipe. If you are following a strict diet please note changing anything will cause the nutritional info to change. My calculations are intended as a guide only.