Combine raspberry preserves and 30 ml water in a medium saucepan over medium heat. Bring to a gentle boil and cook, stirring, for 3-5 minutes until smooth.

Make a slurry using the remaining 15 ml water and cornstarch. Stir it into the hot raspberry sauce, simmering for 1 minute. Strain through a fine mesh sieve into a heatproof bowl and cool.

Preheat your oven to 163°C. Line a 23 x 33 cm baking pan with parchment paper. Crush chocolate sandwich cookies finely in a food processor, add melted butter, pulse to combine, and press evenly into the pan.

Bake the crust for 10 minutes. Remove and let cool.

Place white chocolate chips in a heat-safe bowl. Heat heavy cream until hot and steaming; pour over the chocolate chips and let stand for 5 minutes. Whisk until smooth.

Beat cream cheese and powdered sugar in a large bowl until smooth. Gradually blend in the cooled white chocolate ganache, then mix in Greek yogurt. Add eggs one at a time, mixing until combined.

Spread half of the cheesecake mixture over the cooled crust. Drizzle about 160 ml of raspberry sauce evenly on top.

Smooth the remaining cheesecake mixture over, covering all sauce. Drizzle the remaining raspberry sauce and swirl decoratively.

Bake for 45-48 minutes until edges are set and the center slightly wobbles.

Remove and let cool to room temperature.

Wrap the cooled bars and refrigerate for 4-6 hours or overnight before cutting into squares.

Optional: Garnish with fresh raspberries.