Prepare the raspberry sauce: In a saucepan, combine raspberries, sugar, and 2 tablespoons of water. Bring to a simmer and cook for 5–7 minutes until berries break down. In a small bowl, whisk cornstarch with remaining 1 tablespoon water, then stir into sauce. Simmer until thickened. Strain through a fine mesh sieve to remove seeds. Set aside to cool.
Make the crust: Preheat oven to 325°F (160°C). In a bowl, mix Oreo crumbs with melted butter until combined. Press firmly into the bottom of a 9-inch springform pan. Bake for 10 minutes, then let cool.
Melt the white chocolate: In a heatproof bowl, melt white chocolate chips over a double boiler or in 20-second intervals in the microwave, stirring until smooth. Let cool slightly.
Prepare the cheesecake batter: In a large mixing bowl, beat cream cheese and sugar until smooth. Add eggs one at a time, mixing on low speed. Stir in almond extract, vanilla extract, and flour. Mix in melted white chocolate, then fold in sour cream until creamy.
Assemble the cheesecake: Pour half the batter into the prepared crust. Drizzle half of the raspberry sauce over the top and swirl with a knife. Add remaining batter, then top with remaining raspberry sauce, swirling again for a marbled effect.
Bake: Place the springform pan on a baking sheet. Bake at 325°F for 60–70 minutes, until the center is just set and slightly jiggly.
Cool and chill: Turn off oven, crack the door, and let cheesecake sit for 1 hour. Remove and cool completely at room temperature, then refrigerate at least 4 hours or overnight.
Garnish and serve: Before serving, top cheesecake with fresh raspberries and white chocolate curls. Slice and enjoy!