Preparation:

1: Prepare the base

Place the Marie biscuits into a food processor and pulse until you have fine crumbs. Alternatively, place them in a zip-lock bag and crush with a rolling pin. Transfer the crumbs to a large mixing bowl. Add the desiccated coconut and caster sugar. Pour the melted butter over the dry ingredients and mix thoroughly until the mixture resembles wet sand.

2: Press and chill the base

Line a 20x30cm rectangular slice tin with baking paper, ensuring the edges hang over for easy removal. Press the biscuit mixture firmly into the base of the tin using the back of a spoon or a flat-bottomed glass to create an even layer. Place the base in the refrigerator to chill for at least 30 minutes while you prepare the topping.

3: Make the passionfruit filling

In a large bowl, pour in the sweetened condensed milk. Add the lemon juice slowly while whisking continuously; the acidity will naturally thicken the mixture. Add in the passionfruit pulp and lemon zest (if using), stirring gently to combine. The mixture should be smooth, creamy, and thick.

4: Assemble the slice

Remove the chilled base from the fridge and pour the passionfruit mixture over it. Spread it evenly using a spatula or the back of a spoon. Smooth the surface. Return the slice to the refrigerator and allow it to set for at least 4 hours, ideally overnight, for a firmer texture.

5: Optional passionfruit glaze

For an added punch of passionfruit flavour and an attractive glossy finish, mix the passionfruit pulp with icing sugar and lemon juice. Drizzle this over the top of the slice once it’s set. Allow it to chill for another 30 minutes before slicing.