Peach & bourbon caramel sundaes

Sterilise a 250g jar. Cover the base of a 24-26cm nonstick frying pan with 125g sugar. Set over a medium-high heat and leave to melt and turn a dark amber, without stirring (about 7-10 minutes). Towards the end you can swirl the pan to encourage the last sugar granules to melt. Remove from the heat and whisk in 150ml double cream (take care as it will bubble and spit), then add the bourbon and sea salt flakes (if at this stage there is a little crystallisation, strain the hot caramel through a metal sieve). Pour into the sterilised jar, seal and chill.

Cut 4 of the peach halves into 1cm cubes, then put in a pan with 2 tbsp sugar, the rosemary sprigs and 150ml water. Bring to the boil, then simmer for 10-15 minutes until the fruit is soft and most of the water has evaporated. Discard the rosemary and use a small blender or food processor to whizz the fruit to a purée. Transfer to a lidded container; cool, cover and chill until needed.

Just before serving, sit the sealed jar of caramel in a bowl filled with just-boiled water so the caramel becomes warm and runny. To serve, thinly slice the remaining peaches and whisk the remaining cream almost to soft peaks. Assemble the sundaes in tall glasses, alternating the peach purée with ice cream, caramel sauce and peach slices. Top with a dollop of whipped cream and the crumbled amaretti biscuits or flaked almonds, if using.