Step 1

Heat oven to 190C/fan 170C/gas Put the chopped apples, lemon zest, rosemary, if using, and sugar in a saucepan. Add the lemon juice and cook for 3-4 mins. Tip in the pears and cook 2-3 mins more, until the fruits are just beginning to soften. Spoon the fruits and juices into a 1.7 litre pudding dish and flatten slightly.

Step 2

For the crumble, finely chop half the walnuts in a food processor until reduced to the consistency of ground almonds. Add the flour, butter and sugar and continue to blitz to a coarse or fine crumble mix, whichever you prefer.

Step 3

Roughly break the remaining walnuts with your fingers and stir into the crumble. Scatter the crumble mix on top of the fruits and bake for 20-25 mins until golden brown. Serve warm with cream or custard.