Preheat the Oven:
Preheat your oven to 325°F (163°C). Prepare a 9-inch springform pan by greasing the sides and lining the bottom with parchment paper.

Make the Crust:
In a medium bowl, combine the graham cracker crumbs, sugar, and cinnamon (if using). Stir in the melted butter until the mixture resembles wet sand. Press the mixture into the bottom of the prepared springform pan, making an even layer. Bake for 10-12 minutes, or until the crust is lightly golden. Remove from the oven and set aside to cool.

Make the Filling:
In a large mixing bowl, beat the softened cream cheese with an electric mixer until smooth and creamy. Add the sugar, sour cream, and heavy cream, and beat until combined and smooth.
Add the eggs one at a time, mixing well after each addition. Stir in the lemon zest, lemon juice, vanilla extract, and a pinch of salt. Mix until smooth and fully combined.

Bake the Cheesecake:
Pour the cheesecake batter into the cooled crust. Smooth the top with a spatula. Tap the pan on the counter a few times to release any air bubbles.
Bake the cheesecake for 55-65 minutes, or until the edges are set and the center is slightly jiggly. Turn off the oven, crack the oven door, and let the cheesecake cool in the oven for about 1 hour. This helps prevent cracking.

Chill the Cheesecake:
After the cheesecake has cooled to room temperature, cover it and refrigerate for at least 4 hours, or overnight, to fully set.

Make the Lemon Topping (optional):
In a small saucepan, combine the fresh lemon juice and sugar. Heat over medium heat, stirring until the sugar is dissolved. Remove from heat and stir in the lemon zest. Let it cool to room temperature before spreading over the cheesecake.

Serve:
Once the cheesecake is fully chilled and set, remove it from the springform pan. Optionally, drizzle with the lemon topping and garnish with additional lemon zest or whipped cream. Slice and serve chilled.