Preheat the oven to 160°C / 320°F. Spray the bottom and sides of a 20cm / 8-inch springform pan with the spray cooking oil.

Make the crust: place the digestive cookies or graham crackers, melted butter, and a pinch of fleur de sel in a food processor and pulse until the mixture is finely crumbly. Press the crumb mixture firmly and evenly onto the bottom and up the sides of the prepared springform pan. Refrigerate the crust while you make the filling.

Make the filling: in a stand mixer (or with a handheld mixer), beat the cream cheese, ricotta cheese, quark cheese, white sugar, and brown sugar until light and smooth and no lumps remain. Add the eggs one at a time, beating briefly after each egg until just combined. Stir in the scraped seeds from the vanilla pod, the orange zest, and a pinch of fleur de sel.

Wrap foil tightly around the bottom and sides of the springform pan to protect it from water. Pour the cheesecake filling evenly into the prepared crust.

Place the wrapped springform pan in a large roasting dish. Carefully pour boiling water into the roasting dish until it reaches about halfway up the sides of the springform pan (water bath).

Bake at 160°C / 320°F for about 1 hour 15 minutes to 1 hour 30 minutes, or until a thermometer inserted into the center reads 65°C / 150°F, the outer edges are set, and the center still jiggles slightly.

When baking is complete, carefully remove the roasting dish from the oven, lift the springform pan out of the water bath, unwrap and remove the foil, and set the pan on a wire rack to cool until no longer warm. Refrigerate the cheesecake in its pan for at least 5–7 hours or overnight.

While the cheesecake chills, make the raspberry sauce: in a small saucepan combine the frozen raspberries, 70g white sugar, and 75ml water. Bring to a gentle boil over medium heat, stirring occasionally.

In a small cup, dissolve the 2 teaspoons cornstarch in 1 tablespoon of warm water to make a slurry. Stir the slurry into the simmering raspberry mixture and cook over medium-low heat, stirring, for about 4–5 minutes or until the sauce has thickened slightly.

Remove the sauce from the heat and let it cool to room temperature. Once the cheesecake is fully chilled, pour the cooled raspberry sauce over the top, spread gently if needed, and serve.

Store any leftovers in an airtight container in the refrigerator for up to 3 days.