Prepare the Base: Line an 18 cm springform pan with baking paper. Melt the butter in a small saucepan and set aside. Crush the oat biscuits into fine crumbs using a blender, or place them in a sealable bag and crush with a rolling pin. Mix the crumbs with the melted butter and press firmly into the bottom of the pan.
Create the Cream Filling: In a mixing bowl, combine Greek yogurt, cream cheese, sugar, vanilla paste, and lemon juice. Stir until the mixture is smooth and creamy.
Soak the Gelatine: Soak 6 sheets of gelatine in cold water for about 5 minutes. Meanwhile, in a small saucepan, gently heat the moist gelatine until it dissolves (do not boil).
Combine Gelatine with Cream: Take 2-3 tablespoons of the yogurt mixture, add it to the melted gelatine, and mix well until combined. Allow it to return to room temperature before fully incorporating it into the yogurt mixture.
Whip the Cream: In another bowl, whip the cream until stiff peaks form. Gently fold the whipped cream into the yogurt mixture until smooth and fluffy.
Assemble the Cake: Spread a thin layer of the yogurt cream on the biscuit base, then place raspberries closely together over the cream. Pour the remaining yogurt mixture on top, smoothing it out evenly. Refrigerate the cake for about 4 hours to set.
Prepare the Topping: For the raspberry topping, puree the 200g of raspberries with vanilla sugar, then strain through a fine sieve. Soak the red gelatine in cold water, then heat the raspberry puree slightly and dissolve the gelatine in it. Allow it to cool.
Serve: Once the cake is set, carefully remove it from the springform pan using a knife. Pour the chilled raspberry puree over the cake, allowing it to drip down the sides. Decorate with fresh raspberries and optional edible flowers for a finishing touch.
