Preheat the oven to 350°F (175°C) . Lightly grease a 9-inch springform pan. Wrap the outside bottom and sides of the pan securely with two layers of heavy-duty aluminum foil to protect it from the water bath.

Combine the graham cracker crumbs, granulated sugar, and melted butter. Stir until the crumbs are evenly moistened and resemble wet sand. Press the mixture firmly into the bottom of the prepared springform pan.

Bake the crust at 350°F (175°C) for 10 minutes. Remove it from the oven and place the pan on a wire rack. Reduce the oven temperature to 325°F (165°C) . Let the crust cool slightly while you prepare the remaining components.

Combine the raspberries, granulated sugar, and lemon juice in a medium saucepan over medium heat. Cook for 4–5 minutes, stirring and gently crushing the berries, until they release their juices. Mix the cornstarch and water in a small bowl, then stir the slurry into the raspberries. Cook for another 1–2 minutes, until the sauce thickens slightly.

Press the raspberry mixture through a fine-mesh strainer to remove the seeds. Set the smooth sauce aside to cool. It should be thick enough to drizzle but still fluid enough to swirl through the cheesecake.

Place the chopped white chocolate in a microwave-safe bowl. Microwave at 50% power in 20-second intervals, stirring thoroughly after each interval, until smooth. Set aside for about 5 minutes so it cools slightly but remains fluid.

In a large mixing bowl, beat the softened cream cheese on low to medium-low speed until smooth. Add the granulated sugar and mix just until combined. Scrape down the bowl. Avoid beating aggressively, as incorporating excessive air can contribute to cracks.

Mix in the sour cream and vanilla extract on low speed. Slowly pour in the melted white chocolate and mix until the filling is smooth and uniform. If the white chocolate begins firming before it is fully incorporated, continue mixing gently until no streaks remain.

Add the eggs one at a time on low speed. Mix only until each egg disappears into the filling before adding the next. Scrape the bowl and fold the mixture gently once or twice by hand. The finished batter should be smooth and creamy without looking foamy.

Pour about half of the cheesecake filling over the crust. Drizzle about one-third of the raspberry sauce over the filling. Add the remaining cheesecake batter, then spoon another third of the raspberry sauce over the top in small pools. Reserve the final third of the sauce for serving.

Run a thin knife or skewer gently through the raspberry sauce and cheesecake batter. Use only a few sweeping motions. Do not overmix, or the distinct raspberry ribbons will disappear.

Place the springform pan inside a large roasting pan. Carefully pour hot water into the roasting pan until it reaches about halfway up the sides of the springform pan. Transfer the roasting pan carefully to the oven.

Bake at 325°F (165°C) for 60–70 minutes . The outer 2–3 inches should look set while the center still has a gentle wobble when the pan is nudged. For food safety, the egg-based center should reach at least 160°F (71°C) . Avoid baking until the center becomes rigid.

Turn off the oven and crack the door open. Leave the cheesecake inside the turned-off oven for 1 hour. Remove it from the water bath, discard the foil, and transfer the cheesecake to a wire rack. Cool at room temperature for another 1 hour.

Cover the cooled cheesecake without pressing wrap directly onto the surface. Refrigerate for at least 6 hours, preferably overnight. The filling should become fully firm and sliceable.

Run a thin knife around the edge before releasing the springform ring. Spoon the reserved raspberry sauce over individual slices or lightly over the cheesecake. Add optional fresh raspberries and white chocolate curls just before serving.