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Makes: 6 slices
Prep time: 30 minutes

When you cook onions really, really slowly they release all their liquid and become super sweet and super sticky. With a dash of balsamic vinegar and a spot of sugar added to the mix you have some luxurious strands of sweet lightly pickled onions. Now we know pickled onions are best served with a good hunk of cheddar, so imagine how good this tastes in the form of a warm, oozing tart. – Yuuuum!

1 portion of pastry
a good knob of butter
6 medium sized white onions, finely sliced
1 tablespoon of good balsamic vinegar
1 teaspoon brown sugar
3 egg yolks
150ml double cream
150g mature cheddar cheese, grated

Roll out the pastry on a lightly floured surface then line a 25cm tart case. Chill in the fridge or freezer for 20 mins.

Heat oven to 200C. Line the case with baking paper and fill with baking beans. Bake blind for 20 minutes, then remove the paper and beans and finish baking for a further 10 minutes until the pastry is golden. Leave to cool in the case, then carefully trim the edges of the pastry

While the pastry is cooling, heat the butter in a pan and cook the onions over a lowish heat for 20 mins, stirring occasionally. Add the balsamic vinegar and sugar and finish cooking for a further 10 minutes until they become sticky and golden. You must make sure all the liquid has been evapourated. Take them off the heat and let them cool a little.

Meanwhile, gently beat together the eggs and cream. Add in the cheese and pickled onion, then season with salt and pepper. Fill the tart case with the filling then bake for 20-25 mins until just set and golden.