Step 1: Building the Base

1. Preheat the oven to 170°C (top/bottom heat) or 145°C (fan).
2. Line the bottom of an 18 cm springform pan with parchment paper.
3. Crush the oat cookies and zwieback in a sealed bag using a rolling pin.
4. Melt the butter and mix with the crumbs and salt.
5. Press into the pan to form a base and bake for 10 minutes.

Step 2: Mixing the Dreamy Filling

1. In a bowl, mix ¼ of the cream cheese with cornstarch and 20 g of sugar for about 3 minutes on low speed.
2. Gradually incorporate the rest of the cream cheese.
3. On high speed, add the remaining sugar and vanilla sugar.
4. Mix in the eggs one at a time.
5. Lastly, blend in the heavy cream, mixing only until just combined.

Step 3: Baking to Perfection

1. Wrap the outside of the springform pan with aluminum foil.
2. Pour the cheesecake mixture onto the baked crust.
3. Place the pan in a larger ovenproof dish filled with hot water so that the water reaches about 2.5 cm up the sides of the pan.
4. Bake for 1 to 1.5 hours until the filling is set with only a slight wobble.
5. If the top starts browning too much, reduce the heat to 150°C.

Step 4: Cooling & Setting

1. Remove the cheesecake from the oven and take off the foil.
2. Let it cool for 1 hour at room temperature.
3. Cover with plastic wrap and refrigerate for at least 4 hours (ideally overnight).

Step 5: Decorating with Easter Charm

1. Carefully remove the cheesecake from the pan.
2. Melt the chocolate and use it to attach the bunny cookies around the edge of the cake.
3. Place an Easter bunny cookie cutter in the center and fill the space with crumbled oat cookies to create a decorative design.
4. Top with Giotto truffles for an extra festive touch.