Time to prepare: 20 mins
Time to cook: 35 mins
Dietary requirements: Halal, Kosher, Vegan (with substitutions)
For the walnut pastry:
½ tsp salt
8 tbsp vegetable oil
2 tbsp water
50g walnuts, roughly chopped
For the filling:
2–3 tbsp olive oil
2 large onions, finely sliced
3 tbsp vegetarian or vegan* pesto
600g ripe tomatoes, thinly sliced
Salt and black pepper
A few basil leaves to garnish
Preheat the oven to 200°C/400°F/gas mark 6.
Make the pastry: put the flour and salt into a bowl, pour in the oil and water, mix gently with a fork until it holds together, then stir in walnuts. Using your fingers press the mixture into a flan dish, covering the base as evenly as you can, and pushing up the sides a bit (high crust not needed). Put into the oven – no need to weigh down – and bake for 6–8 minutes. Remove from oven.
Meanwhile heat 1 tbsp of the olive oil in a pan, add the onions, cover and cook gently for 10–15 minutes until tender.
Drizzle the pesto over the pastry, then put the onions in an even layer. Arrange the sliced tomatoes on top, slightly overlapping, to cover the tart completely. Sprinkle with some salt, grind some black pepper over and drizzle with the remaining olive oil.
Put the tart back in the oven and bake for 8–10 minutes to cook the tomatoes a little. Scatter with torn basil leaves and serve.