How to turn spent lemon rinds into a classic tart – recipe

While digging through the compost bins at our restaurant, Poco, in Bristol, spent lemon rinds were one of the first food-waste products that we identified as a potential new ingredient. Later, at Slow Food’s Terra Madre conference in Italy, I came across a delicious lemon marmalade in which the rinds were cut into small shards, and that inspired this recipe.

Stock leftover lemon rinds in the fridge or freezer, ready to use on demand. Fry slices to add to salads, preserve them in salt, or make them into an oh-so-tasty spent lemon rind marmalade, to spread on toast or to upcycle into a tart, from my book Eating for Pleasure, People & Planet. To make it, cut 300g spent lemon rinds into rough pieces, then pulse-blend into 3-5mm pieces. Put these in a pan with a litre and a half of water, bring to a boil, then turn down the heat and simmer for about 35 minutes, until the peel is soft. Add 600g sugar, boil for a further 20 minutes, stirring regularly, until it thickens, then store in a 500ml sterilised jar.

Spent lemon rind marmalade tart

This tart encapsulates the idea of root-to-fruit eating, taking an ingredient that would have otherwise gone to waste and elevating it to a scrumptious dessert. It’s a bit like a vegan version of the River Cafe’s famous lemon tart, but feel free to use non-vegan shortcrust if you have some to hand. The pastry, which is super-nutty, nutritious and flavourful, is crumbly but very forgiving, and can be moulded into place.

Makes 1 x 20cm tart or 3 x 8cm tarts, or enough to serve 6

For the pastry
120g mixed nuts and seeds, toasted in a dry pan, then ground to a flour in a food processor
80g wholemeal flour (eg khorasan, spelt, wheat)
80g buckwheat flour (or an extra 80g wholemeal flour)
40g ground flax or linseeds
60g unrefined sugar (optional)
60ml extra-virgin olive oil, plus extra for greasing

For the filling
400g silken tofu, drained (organic or biodynamic, for preference)
250g lemon marmalade (see above)
1½ tbsp cornflour
¼ tsp dried turmeric
4 tbsp extra-virgin olive oil
Yoghurt of your choice, to serve

Pulse-blend all the pastry ingredients and 80ml cold water until they come together into a dough. Turn out into a bowl, knead lightly and shape into a ball. Cover and put in the fridge to rest for half an hour (or keep in the fridge for up to two weeks).

Using your fingertips, gently press the pastry into a 20cm tart case (or three 8cm ones) until it is an even thickness of about 3–5mm. Cut off any excess pastry overhang and save or bake into biscuits, then prick the base of the tart all over with a fork, so the pastry won’t puff up in the oven. Bake for 15 minutes in a 180C (160C fan)/350F/gas 4 oven, then set aside to cool in the tin(s).

Meanwhile, make the filling. Drain the tofu, wrap it in a clean tea towel and press out any excess moisture. Next, blend the tofu with the marmalade, cornflour, turmeric and oil until very smooth. Pour the filling into tart case(s) and bake in a 190C (170C fan)/375F/gas 5 oven for 15 minutes. Remove from the oven, then scorch the top slightly with a blowtorch or under a very hot grill, taking care not to burn the pastry.

Serve with a spoonful of your favourite yoghurt and a dollop of extra lemon marmalade.