1-Prepare crust: Crush graham crackers into fine crumbs. Mix with sugar and melted butter until combined. Press firmly into the bottom and sides of a 9-inch pie or springform pan. Freeze for 10 minutes to set.

2-Make filling: Beat cream cheese until smooth. Gradually add sweetened condensed milk, mixing until fully incorporated. Stir in lemon juice and vanilla. Pour filling into crust and smooth the top.

3-Prepare berry sauces: Combine raspberries, 2 tablespoons sugar, 2 tablespoons water, juice of half a lemon, and 1/2 teaspoon cornstarch in a saucepan. Simmer over medium-high heat for 10 minutes, until berries break down and sauce thickens. Cool completely, then strain through a fine mesh sieve to remove seeds. Repeat the same process with blueberries, 1 tablespoon sugar, 2 tablespoons water, juice of half a lemon, and 1/2 teaspoon cornstarch. Cool and strain.

4-Create swirl: Transfer each sauce to a separate sandwich bag and snip a small corner off each. Pipe alternating circles of raspberry and blueberry sauce onto the cheesecake, starting from the center and moving outward. Use a wooden skewer to drag lines from the center toward the crust, forming a decorative swirl pattern.

5-Chill: Cover with plastic wrap and refrigerate for 3-24 hours (overnight recommended) before serving.