Preheat your oven to 325°F (163°C) and grease a 9-inch springform pan.

In a medium mixing bowl, combine graham cracker crumbs, 1/4 cup of granulated sugar, and melted unsalted butter. Press the mixture into the bottom of the greased pan.

Bake the crust for 8-10 minutes until slightly golden, then let it cool.

In a large bowl, beat softened cream cheese and 1 cup of sugar together until smooth. Add vanilla extract and eggs one at a time until just combined.

Pour half the creamy filling over the cooled crust, then spread 1/2 cup of blackberry jam over it. Add the remaining filling on top.

Spoon another 1/2 cup of blackberry jam over the cream cheese layer and swirl it gently with a knife.

Bake for 50-60 minutes until the center is slightly jiggly. Cool for about 10 minutes before loosening from the pan.

Chill in the refrigerator for at least 4 hours or overnight. Top with fresh blackberries and raspberries before serving.