Step 1: Prepare the Graham Cracker Crust

Begin by preheating your oven to 325°F (163°C). This lower temperature helps the cheesecake bake evenly and prevents cracking. Next, grease a 9-inch springform pan. The springform pan is essential for easily releasing the cheesecake once it's cooled. Ensure you grease the bottom and sides thoroughly to prevent sticking.

In a medium-sized bowl, combine the graham cracker crumbs, melted butter, and sugar. Use a fork or your hands to mix the ingredients until the crumbs are evenly moistened. The mixture should resemble wet sand. Press the crumb mixture firmly into the bottom of the prepared springform pan. Use the bottom of a measuring cup or a flat-bottomed glass to help create an even and compact crust. This will ensure a stable foundation for the cheesecake filling.

Step 2: Make the Cheesecake Filling

In a large mixing bowl, beat the softened cream cheese with an electric mixer (stand mixer or hand mixer) until smooth and creamy. This is a crucial step, as any lumps in the cream cheese will affect the final texture of the cheesecake. Continue beating for several minutes until the cream cheese is light and airy.

Gradually add the sugar, beating until well combined. Be careful not to overbeat at this stage, as it can incorporate too much air into the batter, which can cause the cheesecake to crack during baking. Stir in the vanilla extract for added flavor.

Step 3: Incorporate the Eggs and Sour Cream

Add the eggs one at a time, beating well after each addition. Make sure each egg is fully incorporated before adding the next. Again, be careful not to overbeat the batter.

Finally, fold in the sour cream until just combined. Gently fold the sour cream to maintain the smooth and creamy texture of the filling. Overmixing at this stage can also lead to cracking.

Step 4: Create the Strawberry Swirl

In a blender or food processor, combine the diced strawberries, sugar, and lemon juice. Blend until smooth. The lemon juice helps to brighten the flavor of the strawberries and adds a touch of acidity.

Step 5: Assemble and Bake the Cheesecake

Pour the cheesecake filling over the prepared graham cracker crust in the springform pan. Gently smooth the top of the filling with a spatula.

Drop spoonfuls of the strawberry puree evenly over the cheesecake batter. Use a knife or skewer to create swirls by gently running it through the batter. Be careful not to over-swirl, as this can muddy the colors and create a less defined swirl pattern. Aim for a marbled effect.

Bake in the preheated oven for approximately 55-60 minutes, or until the center of the cheesecake is set but still has a slight jiggle. The edges should be set and slightly golden brown.

Step 6: Cool and Chill the Cheesecake

Turn off the oven and prop the oven door slightly open. Allow the cheesecake to cool in the oven for about an hour. This gradual cooling process helps to prevent cracking.

Remove the cheesecake from the oven and let it cool completely at room temperature. Once cooled, cover the cheesecake with plastic wrap and refrigerate for at least 4 hours, or preferably overnight. Chilling allows the cheesecake to fully set and develop its flavors.