So simple… yet so sumptuous! But do allow the time to invest in the low, slow sautéeing of the onions; this is the little bit of faff that makes a big difference to the deeply flavoursome end result.
Ingredients (vegetarian; serves 6)
300g shortcrust pastry
1 tbsp butter
2 tbsp olive oil
900g onions, peeled and sliced
2 eggs
300ml double cream
50g parmesan, finely grated
Method
Heat the butter and oil in a large frying pan. Gently sauté the onions over a low heat (stirring occasionally) for about 30 minutes until completely softened and almost ‘jammy’ but still pale in colour.
Meanwhile, preheat the oven to 190°C/gas mark 5. On a lightly floured surface, roll the pastry out to around the thickness of a £1 coin and use it to line a deep, 23cm fluted flan/tart tin. Line the pastry case with baking paper, fill with baking beans and bake blind for 10 minutes. Remove the baking paper and beans and bake for another 8-10 minutes or so, or until the pastry is lightly golden brown. Remove the pastry case from the oven and preheat a baking tray.
Beat the eggs and cream together in a bowl, add the cheese and season to taste. Stir the onions into the mixture, then spoon the filling into the flan/tart case. Bake on the preheated baking tray for 25-35 minutes until the filling is lightly set (a bit of ‘wobble’ is good) and golden brown on top.
Allow to stand for 5-10 minutes before slicing and serving with, perhaps, a crisp green salad.