For the Crust: Make your Butter Cookie crumbs by using a food processor or simply place in a plastic bag and crush using a rolling pin. Mix Butter Cookie, sugar and melted butter in a bowl. Spread in the bottom of a 9" springform pan and up 1 1/2 inch on the side and freeze.
For the Filling: Preheat Oven at 350°F Using an electric mixer blend cream cheese on low speed in a mixing bowl. Use spatula to scrape sides and paddle of mixer. Add in the sugar slowly, and continue to beat until creamy. Add in Key Lime juice and zest and vanilla extract and continue to mix. Add in eggs and yolk one at a time and continue to mix a lowest speed until eggs and yolks are incorporated in the batter.
Pour the mixture into your crust and use offset spatula to scoop out the batter. Bake for 1 hour or until center jiggles and the top is slightly brown Remove from oven and let cool on a wire rack.
For the Topping: Mix sour cream, sugar and Key Lime juice in a small bowl. Spread on cheesecake and return to oven for 10 minutes. Remove from oven and let cool on a wire rack.
Place in the refrigerator and allow to set. Serve and enjoy your Key Lime Cheesecake.