Prepare Raspberry Sauce: In a medium saucepan, combine raspberry preserves with water and heat over medium heat. Bring mixture to a boil and stir in cornstarch slurry until thickened, about 2-3 minutes. Remove from heat and strain sauce through a fine mesh sieve to eliminate seeds. Allow to cool completely.

Make the Crust: In a food processor, crush chocolate sandwich cookies until fine crumbs form, then mix with melted unsalted butter. Press mixture evenly into the bottom of a parchment-lined baking pan. Bake for 10 minutes and let cool.

Prepare Cheesecake Filling: Heat heavy cream over low heat until warm, pour over white chocolate chips, whisk until smooth. In a mixing bowl, beat cream cheese and powdered sugar until creamy; gradually mix in chocolate mixture and Greek yogurt. Incorporate eggs one at a time, mixing well after each.

Assemble Bars: Pour half of cheesecake filling onto cooled crust. Drizzle cooled raspberry sauce over, lightly swirl it, then spread remaining filling on top and drizzle remaining sauce, swirling once more.

Bake: Place the cheesecake bars in the preheated oven and bake for 45-48 minutes. The edges should be set while the center jiggles slightly. Let cool on counter.

Cool and Refrigerate: Allow bars to cool at room temperature for 30 minutes. Cover and refrigerate for at least 4-6 hours or ideally overnight to set completely.