Grease a 22cm spring form cake tin with cooking oil and line with baking paper.
1. Base Blitz the crackers in a blender or crush them in a mixing bowl with the end of a rolling pin. Mix in the butter, then press the mixture into the base of the cake tin using the back of a spoon. Leave to chill.
2. Mix the gelatin into the stock. Microwave for 45 seconds to 1 minute (don’t boil) to dissolve the gelatin, or put the cup in hot water and stir until the gelatin is dissolved. Leave to cool for 5 minutes.