Step 1

Place jelly crystals in a small bowl. Add 1 cup (250ml) boiling water and stir to dissolve. Refrigerate for 30 minutes until cold and just starting to set.

Step 2

Blitz biscuits in a food processor into a fine crumb. Add butter and pulse until well combined. Tip into a 3cm-deep, 18cm x 28cm (top measurement) slice tin that has been greased and lined with baking paper, leaving enough paper overhanging to lift the finished slice out of the tin. Press biscuits into a firm even layer in the tin with the back of a large spoon. Refrigerate for 30 minutes.

Step 3

In the bowl of a stand mixer or using hand-held beaters, whip cream until just starting to thicken. Add cooled jelly and continue beating for 3-4 minutes until just thick (do not overbeat). Pour over biscuit base in tin and smooth the top. Refrigerate for at least 3 hours to set.

Step 4

Use overhanging baking paper to lift slice out of tin and place on a chopping board. Cut into squares to serve.