1. Make the Graham Cracker Crust:

• Preheat Oven: Preheat your oven to 325°F (163°C). Grease a 9-inch springform pan.
• Combine Ingredients: In a medium bowl, combine the graham cracker crumbs and melted butter. Stir until the crumbs are evenly moistened.
• Press into Pan: Press the crumb mixture firmly and evenly into the bottom of the prepared springform pan. Optional: For a crispier crust, bake for 8-10 minutes before adding the filling. Let cool slightly.

2. Make the Lemon Cheesecake Filling:

• Beat Cream Cheese & Sugar: In a large bowl, using an electric mixer (stand mixer with paddle attachment or hand mixer), beat the softened cream cheese, 1 cup granulated sugar, and lemon zest on medium speed until completely smooth and creamy. Scrape down the sides of the bowl as needed.
• Add Eggs: Add the room-temperature eggs one at a time, beating on low speed until just combined after each addition. Do not overmix.
• Add Liquids: Mix in the fresh lemon juice, room-temperature sour cream, and room-temperature heavy cream until well combined and smooth.

3. Assemble and Bake the Cheesecake:

• Pour Filling: Pour the cheesecake filling over the crust in the springform pan. Smooth the top with a spatula.
• Prepare for Baking (Optional Water Bath): Place the springform pan on a baking sheet to catch any drips. Optional but recommended for preventing cracks: Wrap the outside of the springform pan tightly in heavy-duty aluminum foil and place it in a larger roasting pan. Fill the roasting pan with about 1 inch of hot water.
• Bake: Bake for 55-60 minutes, or until the edges are set and the center is still slightly jiggly when the pan is gently shaken.

4. Make the Meringue Topping:

• While the cheesecake is nearing the end of its baking time, prepare the meringue. In a clean, grease-free bowl, using clean beaters, beat the room-temperature egg whites on medium-high speed until soft peaks form.
• Gradually Add Sugar: Gradually add the 1/2 cup granulated sugar, about a tablespoon at a time, while continuing to beat on high speed.
• Beat to Stiff Peaks: Continue beating until the meringue is thick, glossy, and holds stiff peaks (the peak stands straight up when the beaters are lifted).

5. Top and Finish Baking:

• Spread Meringue: Remove the cheesecake from the oven. Spread the meringue evenly over the hot cheesecake, creating decorative swirls or peaks with the back of a spoon.
• Bake Meringue: Return the cheesecake to the oven and bake for an additional 10-15 minutes, or until the meringue is lightly golden brown.

6. Cool and Chill:

• Cool at Room Temperature: Remove the cheesecake from the oven (and water bath, if used). Let it cool completely at room temperature on a wire rack.
• Chill: Once cooled to room temperature, cover the cheesecake loosely with plastic wrap (avoid touching the meringue) and refrigerate for at least 4 hours, or preferably overnight, until completely chilled and set.

7. Serve: Carefully remove the sides of the springform pan before serving. Slice and serve chilled.