1. Crush the chocolate sandwich cookies into fine crumbs using a food processor or rolling pin.

2. In a bowl, mix the crumbs with melted butter until combined. Press the mixture firmly into the bottom of a springform pan to form the base. Chill for 20 minutes.

3. In a large mixing bowl, beat marshmallow fluff and heavy whipping cream until thick, fluffy, and smooth.

4. Spread the marshmallow mixture over the cookie base and smooth the top with a spatula.

5. In a small saucepan, melt dark chocolate chips with sweetened condensed milk over low heat, stirring until glossy.

6. Pour the ganache over the marshmallow layer, spreading evenly.

7. In a skillet, melt 3 tablespoons of butter and brown sugar. Add cereal and toast for 2–3 minutes until coated and golden.

8. Let the cereal topping cool slightly, then sprinkle generously over the ganache.

9. Refrigerate the entire cake for at least 4 hours or overnight to set.

10. Slice with a warm knife and serve chilled.