That old black magic: Skye Gyngell's bewitching blackberry desserts

Growing in abundance in the hedgerows outside Petersham Nurseries, hidden within spiky and unforgiving bushes just by the River Thames, are these beautiful little tart, soft berries, black like ink, plump and heavy.

Blackberries can be found almost everywhere, in back-gardens and fields all over the country. Loved by birds as much as by us, it is often a race to see who gets there first – although happily for us the birds seem drawn to the slightly less ripe fruit still firmly attached to the branches. The blackberries to look for are the softest, heaviest ones just hanging on to the branches – though the fruit that has fallen to the ground is the sweetest of all. Commercial varieties can be found in shops everywhere and can be equally delicious; and for the juiciest berries, go for the ones where the colour is even.

Skye Gyngell is head chef at Petersham Nurseries, Church Lane, Richmond, Surrey, tel: 020 8605 3627, www.petershamnurseries.com

Blackberry crumble

Serves 6

500g/1lb blackberries
The zest and juice of one orange
120g/4oz plain flour
2 tbsp muscovado sugar
120/4oz unsalted butter, cold

Heat your oven to 180C/350F/Gas4. Put the blackberries, orange zest and juice into a bowl and toss together gently using your fingers. Spoon into an ovenproof dish. In a separate bowl, sieve the flour and add the sugar; stir together to combine. Cut the butter into little cubes, add to the flour-sugar mixture and crumble between your finger until you have the texture of sand. If you have a few lumps, all the better. Sprinkle the mix over the blackberries and place on the middle shelf of the oven. Bake for 20-25 minutes or until the berries are bursting around the sides and the top is golden brown. Remove from the oven, allow to cool slightly and serve.

Nectarine sorbet with crushed blackberries

This sorbet is quick and simple. The crushed blackberries on the top lend a tart finish that is most satisfying.

Makes 1 pint of sorbet

6 ripe nectarines
200g/7oz caster sugar
The juice of half a lemon

For the blackberries

200g/7oz blackberries
2 tbsp icing sugar
The zest of one orange

Slice the nectarines in half, remove the stone and chop into one-inch pieces. Place in a blender with the sugar and lemon juice. Purée until smooth; it will have little specks of skin throughout, which is very pretty. Place in an ice-cream maker and follow the manufacturer's instructions.

If you don't own an ice-cream maker, freeze the mix in a low-sided container for two hours. Then remove and drag it with a fork, working from the outside in. Replace in the freezer. Repeat this every half hour three or four times, until all the mixture is formed of ice crystals. This makes a granita; its texture is slightly chewy, but it is just as delicious as any ice-cream.

Place the blackberries in a bowl with the icing sugar. Using the back of a fork, crush roughly; it should have a slightly coarse consistency. Stir in the orange zest and chill. To serve, spoon into chilled glasses and top with the blackberries.

Blackberry, honey and polenta cake

One of my favourite blackberry recipes – soft, slightly sweet and not in the least dry.

Serves 8

4 tbsp honey
200g/7oz blackberries

For the cake mixture

275g/9oz softened, unsalted butter
250g/8oz sugar
200g/7oz plain flour
A pinch of salt
2 tsp baking powder
200g/7oz yellow polenta
3 organic eggs, lightly beaten
100ml/31/2fl oz milk

Place the honey into a small saucepan and gently warm through. When just warm, remove from the stove and pour over the blackberries. Set aside while you make the cake mixture.

Heat the oven to 180C/350F/Gas4. Lightly grease and flour a 28cm cake tin. Cream the butter and sugar together until light and fluffy, then mix in the flour, salt, baking powder and polenta. Add the eggs and milk and stir gently to form a soft dough – the mixture should easily drop from a spoon. Spoon the batter into the cake tin and gently stud the blackberries into the top. Pour over whatever honey is left in the pan and bake on the middle shelf of the oven for an hour and a quarter.

To test whether the cake is cooked, insert a skewer into the centre; it should come out clean. Leave to cool and serve.