1. In a large bowl mix the rolled oats, spelt flour, sugar (or xylitol), and salt until well combined. Add vanilla extract and the cold butter in small pieces. Mix with the dough hooks of a hand mixer (or with your hands) to get different-sized streusels. Place in the fridge for about 20 minutes.

2. Line a 9.5 inches (24cm) springform tin with baking parchment and grease lightly. Transfer about 2/3 of the streusels into the tin and press to the bottom and sides. The edge of the crust should be at least 1.6 inches (4cm) high. Place in the fridge until needed again.

3. Preheat the oven to 350°F (180°C). Wash, dry, halve and pit the plums. Set aside. For the filling, mix the cream cheese, mascarpone, and sugar (or xylitol) in a large bowl. Add the eggs and vanilla extract and mix well. Sift the cornstarch on top and mix in well – no lumps should be visible. Stir about 1/3 of the mixture into the pre-made poppy seed mix. Pour that into the prepared tin and smooth out the top. Carefully add the remaining filling and smooth out the top as well to get even layers. Place the plum halves on top and sprinkle with the remaining streusels. Bake the cake for about 50-55 minutes. Remove from the oven and let cool down completely. Refrigerate for at least 2 hours before serving to allow the cheesecake mixture to set…