Onion tart with greens
I learned to make (and to love) a French onion tart from the recipe in Elizabeth David’s classic French Provincial Cooking. This tart remains faithful to the spirit of that recipe, based as it is on lots of sweet, soft onion, but I’ve added greens, used my half-wholemeal shortcrust pastry and gone for a lighter custard based on half milk, half cream (and whole eggs, so there are no spare whites leftover for you to deal with). It’s still gorgeous. And this is an endlessly adaptable tart template.
Method
Serves 6-8
Use the chilled shortcrust pastry to line a 24cm tart tin and bake blind as per the instructions on page 143. Trim the edges. Preheat the oven to 180°C/160°C Fan/Gas 4. To make the filling, heat the oil and butter together in a large frying pan over a medium-low heat. Add the sliced onions with some salt and pepper. Cook gently, stirring regularly, for about 30 minutes until soft, golden and tender. Grate over some fresh nutmeg, stir in and leave to cool a little. While the onions are cooking, blanch the greens: bring a pan of water to the boil and add the cavolo nero or spinach. Return to a simmer then immediately tip the greens into a colander to drain and run under the cold tap to cool them quickly. Now squeeze out as much moisture from the greens as you can, then chop coarsely and combine with the cooked onion.
Beat the cream, milk and eggs together in a bowl and season well with salt and pepper. Arrange the onion and greens mix in the prepared tart case and carefully pour the beaten egg mixture over them. Scatter the grated cheese over the surface. Bake in the oven for about 30–35 minutes until the filling is just set and golden. Leave the tart to cool, at least a little, before serving warm or at room temperature.
Variations:
Onion and creamy courgette tart:
Instead of the greens, finely slice about 500g small or medium courgettes. Heat a little oil and butter in a frying pan over a moderate heat, then add the sliced courgettes with a good pinch of salt. Sizzle and sweat, stirring regularly. When the liquid runs from the courgettes, you can turn up the heat a bit. Keep cooking,
stirring regularly and crushing the courgettes, until they are very soft and pulpy, without too much browning. You can do this at the same 149 time as you are cooking the onions, dividing your attention between the two pans. Finally, mix the pulpy courgettes with the sweet soft onions, adding a little roughly chopped basil, if you like. Pile into the tart case and spread evenly with a spatula, then pour on the custard, sprinkle over the cheese and bake as for the main recipe.
Onion and asparagus tart: Instead of the greens, trim 12–15 asparagus spears (of their woody ends) and blanch in a pan of well-salted boiling water for 3–5 minutes, until al dente (tender but firm to the bite). Drain and leave to cool. Make the tart as for the main recipe (leaving out the greens). Spread the cooked onions evenly in the tart case and pour on the custard. Arrange the asparagus spears randomly but evenly over the surface, pressing them lightly in, before sprinkling over the cheese. Or, if you prefer, arrange them in a symmetrical star, points to the centre. You might have to trim them to make them fit – but don’t waste the trimmed-off bits, just push them further into the mix, out of sight! Bake as for the onion tart.
Ingredients
1 x quantity of half-wholemeal shortcrust pastry (which can be found on our website)
Chilled flour, to dust
1 tbsp olive or vegetable oil
A large knob of butter
About 600g onions (red, brown or a combination), finely sliced
Nutmeg, for grating
200–250g cavolo nero, tough stalks removed, or about 300g spinach, very well rinsed
150ml double cream
150ml whole milk
3 medium eggs
50g mature Cheddar or Parmesan, grated
Sea salt and black pepper