How to turn a whole beetroot into a mind-blowing chocolate cake – recipe

Whenever possible, I prefer to leave the skin on vegetables, but boiled beetroot skins are unappetisingly papery. So I transform them into a vivid natural food dye to use in both sweet and savoury dishes by dehydrating them in a single layer in the oven (ideally do this alongside other food to save on energy), before cooling and grinding to an all but imperishable powder.

In fact, the whole beetroot plant is edible, with each separate part nutritious and unique in its own way. The leaves can be cooked like any leafy green, while an abundance of stalks can be turned into a rather special candy. To make it, put the stalks in a small saucepan, measure out enough water just to cover them by half, noting the amount in millilitres, then add the same amount of sugar in grams. Bring to a boil and cook until the sugar has thickened into a soft-crack toffee (ie, when it hits 132-143C). Lift out the pieces of caramelised stalk, arrange them spaced apart on a lined tray and leave to cool and harden. Store in a clean, airtight jar or similar, and use to decorate desserts such as today’s cake.

Beetroot nemesis cake
Inspired by the River Cafe’s iconic chocolate nemesis cake, I came up with this to showcase how delicious beetroot can be in its entirety. As in the River Cafe recipe, this cake is irresistibly chocolatey, but the addition of beetroot gives it a deep, ruby-red colour and intriguing depth of flavour. I first cooked it at a food waste banquet I co-created in 2011, and it’s still a favourite of mine today. At that event, which we called The Forgotten Feast, we transformed a warehouse belonging to FareShare, the UK’s largest food redistribution charity, into a restaurant for the weekend. It was a fun event, and a turning point in my career that led to my focus on sustainability, regenerative agriculture and even this column. That weekend, we saved hundreds of kilos of food from being wasted, and the resources that went into producing it and the proceeds went on to help FareShare save many thousands more meals. It was a life-changing moment that helped me realise that even as individuals we really can make a difference.

Enjoy this cake with or without the beetroot skin powder and candied stalks: it’s decadent, rich and comforting either way. It keeps really well in the fridge, so is a great cake to make in advance for dinner parties. It sets well overnight and cuts best when cold. It’s very rich and sweet, so serve in small portions with thick yoghurt or creme fraiche to cut the sweetness.

Serves 10

180g dark chocolate
125g butter
3 large eggs
150g unrefined sugar
150g boiled beetroot

To serve (all optional)
Thick yoghurt or creme fraiche, beetroot skin powder, candied beetroot stalks

Line a 20cm round tin with greaseproof paper. Put the lined tin inside a larger tray in which it can sit comfortably, to make a bain-marie. In a bowl set over a pan of hot but not boiling water, melt together the chocolate and butter. Meanwhile, in a second bowl, whisk the eggs and sugar for five to 10 minutes, until doubled in volume. Puree the beetroot in a blender, fold this into the melted chocolate mix, then fold the lot into the whisked eggs.

Pour into the lined cake tin, then transfer it, still inside the larger tray, to a 170C (150C fan)/325F/gas 3 oven, and fill the outer tray with enough boiling water to come three-quarters of the way up the sides of the cake tin. Bake for about 30 minutes, until just set, then remove, leave to cool and refrigerate.

Cut into small wedges and serve dusted with a pinch of beetroot skin powder, topd with a few candied beetroot stalks and accompanied by a large dollop of yoghurt or creme fraiche.