Red onion, chilli and gruyère tart tatin

 

Serves 4-6

Ingredients

4 medium red onions
1 tbsp olive oil
1 generous tbsp butter
3-4 sprigs fresh thyme
2 tsp mild chilli flakes
2 tbsp balsamic vinegar
250g gruyère cheese, grated
250g plain flour
1 tsp baking powder
1 tsp salt
100 ml milk
40g butter, melted
2 tsp mustard
1 large egg

Method

1. Preheat the oven to 200C/gas 6. Peel the onions, halve them, then cut each half into four, lengthways. Heat the oil and butter in an oven-proof frying pan and cook the onions over a medium heat, stirring regularly, for about 30 min until soft and tinged with colour. Season, and add the thyme and chilli and stir to combine.

2. Add the balsamic vinegar and turn the heat up, reduce until syrupy. Remove from the heat and scatter 100g of the cheese over.

3. Sift the flour, baking powder and salt together in a bowl and add the remaining cheese. In another bowl whisk the milk, melted butter, mustard and egg together well, then pour on to the flour mixture. Mix to a sticky dough using a fork or your hands. Tip it on to a floured work surface and press into a circle about the size of the pan, then transfer it to the pan, pressing it to cover the onions completely and seal the edges.

4. Put it in the oven for 15 min, then reduce the heat to 180C/gas 4 and bake for another 10 min, by which time the dough should be golden and crisp on top. Let it stand for a couple of minutes, then cover with a large plate and turn upside down, so the plate’s beneath. Serve immediately.