If starting with whole graham cracker sheets, break them into rough pieces. Add to a food processor and pulse until you have fine, even crumbs. You need about 2 cups (200g) of crumbs. Alternatively, place crackers in a zip-top bag and crush with a rolling pin.
Melt the butter and allow it to cool for 5 minutes. Pour the melted butter over the graham cracker crumbs, add the granulated sugar, and stir until the mixture looks like wet sand and holds together when squeezed. Pour into a 9-inch springform pan and press firmly and evenly across the bottom. Refrigerate while you prepare the filling.
Remove the cream cheese from the refrigerator at least 1 to 2 hours before you plan to start so it reaches room temperature. If you forgot, cut each block into smaller cubes and let them sit at room temperature for 30 to 45 minutes.
Add the softened cream cheese to the bowl of a stand mixer fitted with the paddle attachment. Beat on medium speed for 2 to 3 minutes until completely smooth and slightly fluffy. Sift in the powdered sugar, add the vanilla extract and lemon juice, and beat for another 2 minutes until fully incorporated.
Pour the cold heavy whipping cream into a separate, clean mixing bowl. Using a hand mixer or stand mixer fitted with the whisk attachment, whip on medium-high speed until stiff peaks form, about 3 to 4 minutes. Be careful not to overwhip.
Add the whipped cream to the cream cheese mixture in two or three additions. Fold gently with a rubber spatula using a slow, sweeping motion from the bottom of the bowl up and over the top until fully combined with no white streaks remaining.
Remove the springform pan from the refrigerator. Pour the filling into the pan on top of the crust. Use an offset spatula to spread the filling evenly and smooth the top. Gently tap the pan on the counter to release any air bubbles.
Cover the springform pan tightly with plastic wrap or aluminum foil. Refrigerate for a minimum of 6 to 8 hours, or preferably overnight, until the filling is firm and set to the touch and no longer jiggles when moved.
Run a thin knife along the inside edge of the pan to release the crust from the sides. Unlatch the springform ring and gently lift it away. Add desired toppings just before serving. For clean slices, use a sharp knife dipped in warm water and wiped dry between each cut.