1. Combine the sugar and water in a pan and bring to the boil, stirring. Continue to boil for 3 minutes. Remove from the heat, add 1 tsp fennel pollen and set aside to infuse, then cool, strain and chill.

2. Whisk the mascarpone, yoghurt and fennel syrup together and churn in an ice-cream maker until frozen (or freeze in a shallow container, stirring to break up the crystals every hour for the first 3 hours).

To make the crunch, mix the sugar, pollen and lemon zest together.

To serve, spoon the crushed pineapple on to dessert plates, top with scoops of ice-cream and scatter with lemon fennel crunch and dill sprigs.