Preheat your oven to 325°F (163°C). Grease a 9-inch springform pan lightly.
Mix graham cracker crumbs, sugar, and melted butter until it feels like wet sand. Press into the pan base and slightly up the sides. Chill in the fridge for 10 minutes.
In a large bowl, beat the cream cheese until smooth. Add sour cream, sugar, eggs, and vanilla. Mix until fully combined and no lumps remain.
Pour the filling into the chilled crust and smooth the top with a spatula.
Warm the strawberry jam or puree slightly if needed, then drop spoonfuls over the cheesecake. Use a knife to gently swirl through the batter.
Bake for 40-45 minutes or until the center is almost set but still jiggles slightly. Let cool completely at room temp, then refrigerate for at least 4 hours or overnight.
Remove the cheesecake from the pan, slice, and serve chilled.