Preheat your oven to 325°F (163°C) and prepare a 9-inch springform pan by greasing it lightly.

In a large mixing bowl, combine the graham cracker crumbs, melted butter, and 1/4 cup of sugar. Mix until well combined and resembles wet sand. Press this mixture firmly into the bottom of the springform pan.

In another bowl, beat the softened cream cheese with an electric mixer on medium speed until smooth. Add in the remaining 3/4 cup of sugar, cocoa powder, eggs, and vanilla extract. Beat until well combined, fluffy, and free of lumps.

Gently fold in the strawberry puree into the batter. Swirl slightly to create that marbled look.

Pour the chocolate cheesecake batter onto the graham cracker crust and use a knife to make swirls with the remaining strawberry puree for decoration.

Bake for 60-70 minutes or until the edges puff up and appear firm while the center may still be slightly jiggly.

After baking, turn off the oven and crack the oven door to let the cheesecake cool gradually for about an hour. Then, chill in the refrigerator for at least 4 hours, preferably overnight.

Unmold the cheesecake, slice, and serve chilled. Garnish with fresh strawberries if desired.