Preheat the oven to 325°F (160°C). Prepare a 9-inch springform pan by greasing the bottom and sides with butter or nonstick spray and placing a circle of parchment on the bottom for easy removal.

Make the crust: in a medium bowl, combine graham cracker crumbs, rolled oats, light brown sugar (crust), ground cinnamon (crust) and salt. Pour in the melted butter and stir until the mixture holds together when pressed. Transfer to the prepared springform pan and press firmly and evenly across the bottom and slightly up the sides to create a compact crust. Chill in the refrigerator while you prepare the filling.

Blend the cottage cheese: place the cottage cheese in a blender or food processor and pulse until mostly smooth with just a few small curds remaining.

Make the filling: in the bowl of a stand mixer fitted with the paddle (or using a large bowl and electric mixers), beat the room-temperature cream cheese on medium speed until smooth and free of lumps, scraping down the bowl as needed. Add granulated sugar and light brown sugar (filling) and beat until well combined and slightly aerated, about 1–2 minutes.

Add the blended cottage cheese and Greek yogurt to the cream cheese mixture and mix on low until incorporated. Beat in the eggs one at a time, mixing just until combined after each addition to avoid over-incorporating air. Stir in the additional egg yolk, pumpkin purée, vanilla extract, fresh lemon juice, ground cinnamon (filling), ground ginger, ground nutmeg, salt and cornstarch; mix on low speed until smooth and uniform in color, scraping the bowl as necessary.

Assemble and smooth: remove the crust from the refrigerator. Pour the filling over the crust and smooth the top with a spatula. Tap the pan gently on the countertop a few times to release any large air bubbles.

Bake in a water bath (recommended for a crack-free finish): wrap the outside of the springform pan with a double layer of heavy-duty foil to prevent water seeping in. Place the wrapped pan in a larger roasting pan and pour hot water into the roasting pan until it reaches about halfway up the side of the springform pan. Transfer to the oven and bake for 55–70 minutes, or until the edges are set but the center still has a slight wobble when the pan is gently shaken. If you prefer not to use a water bath, bake at the same temperature and check at 50 minutes; the cheesecake may brown more and is more likely to crack.

Cool gradually: when the cheesecake is done, turn off the oven and crack the oven door open. Let the cheesecake rest inside the warm oven for 45 minutes to cool slowly and reduce cracking. After that, remove the cheesecake from the water bath carefully and place on a wire rack to cool to room temperature. Once cooled, refrigerate for at least 6 hours, preferably overnight, to fully set.

Prepare the cream topping: in a small bowl, whip the heavy cream with powdered sugar and vanilla extract until soft peaks form. Fold in the Greek yogurt gently to create a silky, slightly tangy topping that’s easy to drizzle. If you prefer a thinner drizzle, whisk the heavy cream and yogurt together with additional milk (1–2 teaspoons) until pourable.

Unmold and top: run a thin knife around the edge of the springform pan to loosen the cheesecake, then release the springform ring and transfer the cake to a serving plate. Spoon or pipe a thin layer of the cream-yogurt drizzle over the top of the cheesecake slice or over the whole cake. Dust lightly with ground cinnamon and scatter toasted pumpkin seeds across the cream.

Serve: slice with a hot, dry knife for clean edges. Wipe the blade between cuts for neat slices. Each slice can be finished with an extra drizzle of yogurt-cream and a few more pepitas, if desired.

Store leftovers covered in the refrigerator for up to 4 days. For longer storage, freeze individual slices wrapped tightly in plastic and foil for up to 2 months; thaw overnight in the refrigerator before serving.