Mix rusk and cookie crumbs (or graham cracker crumbs), 1/2 cup sugar, butter, and 2 tablespoons tahini together in a bowl. Press into the bottom of a 10-inch springform pan. Sprinkle 1/4 crushed pistachios over the prepared crust.
In the bowl of an electric stand mixer, using a whisk attachment, beat the cream cheese and whole egg together until smooth. Beat in the egg yolk. Add the Greek yogurt and vanilla extract, 1 1/4 cups sugar, heavy cream, and flour and whisk until smooth. Spread 2 cups of mixture over the crust to form the first filling layer.
Add the pumpkin puree, cinnamon, cloves, and nutmeg to the remaining cream cheese mixture and whisk to combine. Spread over the first layer of filling.
Place cheesecake in a cold oven. Set oven temperature to 200 degrees F / 95 degrees C. Bake cheesecake slowly, for about 3 hours, or until set. Open oven door a bit and let cheesecake cool inside for 1 hour. Refrigerate until firm, 8 to 24 hours.
To serve: Spread 1/4 cup tahini over the surface of the cheesecake; arrange toasted walnuts and toasted sesame seeds or nigella on top. Expect a WOW moment!