Heat oven to 350°.
In a small bowl mix together all the graham cracker crust ingredients and stir until it's well combined. Press into a 9-inch pie plate. * You want to get a tight crust so press it really well into the pie plate. Use the flat underside of a measuring up to get it pressed into the pie plate well. 1½ cups graham cracker crumbs, 1/3 cup granulated sugar, 6 tablespoons butter
Cook for 7 minutes. Let the crust cool while you prepare the filling.
In a large bowl add the sweetened condensed milk, sour cream, key lime juice, and lime zest. Stir with a whisk until it's combined well and smooth.
2 cans (14 oz each) sweetened condensed milk, 1/2 cup sour cream, 3/4 cup key lime juice, zest from 2 limes
Pour into the graham cracker crust. Bake for 10 minutes.
Let the pie cool for about 20-30 minutes and then cover with saran wrap. Make sure that the saran wrap is touching the top of the key lime pie to prevent condensation from the refrigeration time.
Refrigerate for at least 6 hours or overnight.
When ready to serve beat the heavy whipping cream, powdered sugar, and key lime juice in a bowl until stiff peaks form. This will take several minutes. Start on LOW speed and increase speed as needed as the cream gets thicker.
1½ cups heavy whipping cream, 1/2 cup powdered sugar, 1 tablespoon key lime juice
Pipe the whipped cream onto the pie (as pictured) or serve each slice with a dollop of whipped cream.
zest from 1 lime