Blackberries that grow wild near hedgerows and along canals, rivers and streams are the things of fairy tales. When you chance upon them it is always a thrill. Free food! Whether a shade of under-ripe red or fermenting on the vine, slightly bland or even muddy, one thing’s for sure: the flavour of the berries at arm’s reach are rarely as good as the ones the birds or the annoying guy with the ladder can reach. There are, however, always a handful of gems among the brambles which, mixed in with the others, are perfect for puddings. Foraging for them in the outdoors – in the city or country – makes them taste all the sweeter.

The geranium is a good friend of the blackberry. In fact, geranium is everyone’s friend, because it is so easy to grow. I have one in a tiny pot on my window ledge – next to other easy-growing aromatics, such as thyme, sage, rosemary and bay – which has survived almost a decade. The scented geranium I like best is rose, but the lemon variety is nice for baking too. (A friend even gave me one that smells like Coca-Cola, but I have yet to try it). Infused into cream and mixed into mashed berries, this is the world’s simplest ice-cream to make, but it needs to be eaten on the day, as it will go icy fast.

Made into a purple glaze, blackberries are also great on my favourite style of doughnut, the old-fashioned cake variety. Adding lemon and sugar to the berries in a frozen cream or crackly glaze elevates your foraged bounty or supermarket score to a thing of wicked beauty.

Frozen blackberry-geranium cream

Makes around 2 litres
5 geranium leaves, rinsed, slightly torn
400g double cream
200g caster sugar
1.5kg blackberries

1 Add the geranium leaves to the cream along with 50g of caster sugar. Allow them to steep overnight in the fridge.

2 The next day, macerate the berries in the remaining 150g caster sugar for an hour to extract some juices and sweeten the berries. Whizz the berries and any juices in a food processor or mash with a wooden spoon or mallet.

3 Strain out the leaves and lightly whip the cream. Fold in the berry mash.

4 Transfer to a suitably sized container and freeze for at least 4 hours.

Blackberry cake doughnuts

The dough can be made the day before.

Makes 6
640g extra fine sponge flour
3 tsp baking powder
A grating of nutmeg
2 tsp fine sea salt
Zest of 2 lemons
200g butter
200g sugar
4 egg yolks
300g plain yoghurt
Vegetable oil, for frying

For the glaze
300g blackberries
1 tsp lemon juice
400g icing sugar
½ tsp salt
Hot water

1 First, make the doughnut dough. Sift together the flour and baking powder. Whisk in the nutmeg, salt and lemon zest. Set aside.

2 In the bowl of a stand mixer or with a handheld electric mixer, cream together the butter and sugar – but only until smooth and creamy; not pale and fluffy. Add the yolks one at a time, mixing well after each addition. Add the yoghurt and mix well.

3 Add the dry ingredients to the wet ingredients, and mix them into a dough. Turn out on to a piece of clingfilm. Wrap and chill the dough for 2 hours.

4 On a liberally floured surface, roll the dough out to 2cm thick, and cut out as many doughnuts as you can using a 9cm round cutter. Pat the scraps together and re-roll one more time to get about 6 doughnuts all together. Remove the holes, and fry and glaze them as you do the doughnuts. Score lines on top of each doughnut in a pentagonal pattern.

5 Heat the vegetable oil to 180C/350F. Fry the doughnuts for 4-5 minutes on one side (until golden), and then for 2‑3 minutes on the second side, or until equally golden.

6 To make the glaze, puree the blackberries in a food processor. Strain through a sieve to remove the seeds. Mix with the lemon juice, then add the icing sugar and salt, and whisk to combine. If the glaze is a little thick, you can add a drop of hot water.

7 Dip the warm doughnuts into the glaze, then put on a wire rack to cool with a tray underneath to catch the drips.

• Claire Ptak is a pastry chef, author and food stylist and owns Violet Bakery in London. She is the author of the Violet Bakery Cookbook (Square Peg); @violetcakeslondon