Mr Ivan Tisdall-Downs and Ms Imogen Davis want to make you see London differently. The co-founders of the restaurant Native are known for showcasing wild food in their modern and seriously delicious dishes, and now they’re letting diners in on their foraging secrets with the launch of a lunchtime urban foraging course.

The menu at Native, a vast, light space near London Bridge where indoor trees flank the marble-topped tables, focuses on foraged ingredients, from peppery nasturtium leaves to crunchy Kent ants. They’re paired with carefully sourced produce. Cornish mackerel is served with a heady fish bone caramel and sea-salty samphire, while pink Swaledale duck from North Yorkshire comes with sea herbs and grassy-tasting garden peas. Chef Mr Tisdall-Downs creates dishes that minimise waste, too, such as daily-changing “wasting snacks”, which transform otherwise discarded ingredients into canapés, salad of Isle of Wight tomatoes and “yesterday’s bread”. “The idea of being able to let the land inspire and dictate our menu means we have to be more creative,” says co-founder Ms Davis. “It’s great fun, but also a lot of pressure.”

Launching in late July, the weekend Forage And Feast event series will bring Native’s root-to-plate philosophy to life. Guests will meet Mr Tisdall-Downs and Ms Davis near Native for a guided foraging tour, then head back to the restaurant for a three-course lunch.

The idea of foraging may conjure up images of rural hedgerows and country forests, but Ms Davis and Mr Tisdall-Downs are keen to demonstrate you can find something edible in the tiniest of green spaces. “Get a book and cross-reference your sources before eating anything,” says Ms Davis. “The River Cottage books are a good place to start. Go for something identifiable to begin with, such as blackberries, which can be found in city parks and growing on hedgerows everywhere.” Look out for them from late July until the beginning of October. Once you’ve picked your blackberry haul, try simmering them into a jam. “It makes a great present,” says Ms Davies.

When you’re feeling more adventurous, try looking for small white yarrow flowers, which grow in wide grassy areas and on heathland. “It has a slightly sweet taste with a bitter tone,” says Ms Davis. “Historically, it was used as a charm against bad luck and as a healing herb. We just use it because it tastes good.” Try infusing in hot water to make a fragrant yarrow tea.

Later in the season, sloe berries are abundant in many parks and hedgerows. Look out for indigo-hued fruits on blackthorn bushes, which have pointy black thorns. “It’s amazing how many edible ingredients there are in London parks,” says Ms Davis. The classic way to use sloes is in sloe gin, which is made by steeping the berries with sugar and gin and turning every week or so for a month or two until infused. Or try Native’s sloe gin meringue pie below.

If you’re inspired to try foraging, remember the golden rule – never over-pick. “Only use about a fifth of the plant,” says Ms Davis. “That way, you’ll ensure the next yield won’t be affected.”

1 x 23cm baked shortcrust pastry case 

For the sloe berry curd:

• 300g  sloe berries
• 125g butter
• 350g caster sugar
• Zest and juice of 2 lemons
• 3 medium organic eggs
• 4 medium organic egg yolks 

For the Italian meringue:

• 250g caster sugar
• 4 medium organic egg whites

Place the sloe berries in a saucepan, half cover with water and bring to the boil. Simmer until the flesh leaves the stones, pressing down with a potato masher to help remove the stones.

Once most of the excess water has evaporated, pass the fruit through a fine sieve discarding any pips, stalks and tough skins. You will be left with a fruit purée.

Place the butter, sugar, fruit and lemon zest and juice in a saucepan and stir until the sugar has dissolved and the butter has melted.

In a separate bowl whisk the three eggs and four yolks thoroughly. Remove the fruit mixture from the heat and whisk in the eggs, ensuring they are well incorporated. Place the pan back on a low to medium heat and stir continuously until it has visibly thickened and can coat the back of a spoon, about 10-15 minutes, and it has the consistency of a thick custard. Leave to firm up in the fridge.

For the meringue, add the sugar to a pan along with 50ml water and place on a high heat to reach a temperature of 116°C or until the water has evaporated and the sugar is bubbling away.

Meanwhile, whisk the egg whites on high speed in a stand mixer until they form stiff peaks. When the sugar comes to temperature, slowly and steadily pour it into the egg whites while continuously mixing on a high speed.

Once all the syrup is incorporated, lower the speed to medium and keep mixing until the sides of the bowl have cooled.

Fill the tart case with the cold curd and spoon the Italian meringue mixture on top. Brown the meringue under a hot grill or with a cook’s blow torch, then serve.