Step 1

Grease a 3cm deep 16.5 cm x 26 cm slab pan. Line base and sides with baking paper, allowing a 2 cm overhang at both long ends.

Step 2

Place 12 biscuits, in a single layer, in pan to cover base.

Step 3

Combine custard powder and ¼ cup milk in a saucepan. Whisk until smooth. Pour in remaining milk.

Step 4

Add sugar and place pan over medium heat. Cook, stirring constantly, for 5 minutes or until custard comes to the boil.

Step 5

Cook, stirring constantly, for 2 minutes. Remove from heat.

Step 6

Cover surface of custard with plastic wrap. Set aside for 30 minutes to cool slightly.

Step 7

Pour warm custard over biscuits. Top with another 12 biscuits. Refrigerate for 1 hour or until set.

Step 8

Sift icing sugar into a bowl. Add 1 tablespoon passionfruit pulp. Stir to make a thick icing, adding more pulp if required. Spoon icing over slice.

Step 9

Refrigerate for 1 hour or until icing sets. Cut slice into squares, using shape of biscuits as a guide.