Preheat oven to 175C.

For the lime dust put the leaves on the microwave plate and microwave on high for 2 minutes. Carefully remove the leaves and allow to cool and crisp. Devein the leaves and pound to a powder in a mortar and pestle. If you'd prefer not to have any larger crunchy pieces, sieve the powder into a bowl and set aside.

For the crumble topping combine the ingredients in a bowl and rub in the butter with your fingertips until chunky crumbs form.

Combine the filling ingredients in a bowl and pour into a 30cm diameter round baking dish. Don't worry if you have to pile the pineapple, it cooks down as it bakes. Scatter over the crumble topping then place in the oven and bake for 40-50 minutes. You want the pineapple to soften and caramelise but not be pulpy – it should hold its shape. If the crumble topping is taking on too much colour, cover with foil and then remove for the last few minutes of cooking.

Serve with a scoop of coconut gelato sprinkled with the lime leaf dust.

More summer spins on the humble crumble