1

Preheat the oven to 180°C, fan 160°C, gas mark 4. Grease a 20cm-round fluted loose-bottomed tart tin.

2

Put the walnuts on a baking tray and roast for 5 minutes, until just golden. Set aside to cool slightly, then finely chop.

3

Increase the oven temperature to 190°C, fan 170°C, gas mark 5.

4

Put the plain flour, low-fat spread, 50g Demerara sugar, baking powder, cinnamon and the walnuts in a large bowl and rub together using your fingertips until the mixture resembles coarse breadcrumbs. Press three-quarters of the mixture into the base and up the sides of the prepared tin.

5

Put the plums in a large bowl with 10g Demerara sugar, the cornflour and orange juice and stir to combine. Spoon the plum mixture over the pastry case and sprinkle over the remaining crumble mixture. Put the tin on a baking tray and bake for 40-45 minutes or until golden and bubbling.

6

Set aside to cool for 30 minutes in the tin, then remove from the tin and sieve over the icing sugar, then cut into 8 and serve with 1 tablespoon fat-free natural yogurt per slice.