Preheat the oven to 180 degrees C . Mix biscuit crumbs with butter and press into the base of a 23cm cake tin (with a removable base) until it is even and firm. Bake in the preheated oven for 15 minutes. Then cool and chill in the fridge for at least 3 hours.
Place all the second layer ingredients into a non-stick saucepan and boil over low heat. When the marshmallows have melted, add in the gelatine (which must be dissolved in warm water first and stirred).
Scoop the mixture over the base. Chill again in the fridge for 3 hours, depending on the thickness of the layer. For best results, chill overnight.
When the second layer is ready, mix the jelly with hot water according to packet instructions. Cut the strawberries into half and place them on top of the filling.
When the jelly mixture has cooled – but not hardened - use a tablespoon to scoop the mixture up and form a thin layer to keep the strawberries firmly in their positions.
Place the cake tin into the fridge for 10-15 minutes. When time is up, continue scooping the rest of the mixture and the layers of strawberries onto the cake until the strawberries are used up.