In a medium bowl, combine graham cracker crumbs and melted unsalted butter. Mix until the crumbs are evenly coated and resemble wet sand. Press mixture into the bottom of a 9-inch springform pan. Set aside.

In a large mixing bowl, add softened cream cheese and beat until smooth and creamy, about 2–3 minutes.

Add sour cream and powdered sugar to the whipped cream cheese. Mix on low speed until well combined, about 1–2 minutes.

Pour in the fresh lemon juice and lemon zest. Mix on medium speed for an additional 2–3 minutes until thoroughly incorporated.

Carefully pour the lemon filling over the prepared crust. Use a spatula to spread the mixture evenly. Smooth the top for presentation.

Cover the cheesecake with plastic wrap and refrigerate for at least 4 hours, or overnight for best results.