French onion tart with cheesy thyme pastry

Put the flour in the bowl of a food processor with the 100g butter. Blitz until the mixture resembles fine breadcrumbs, then add 50g of the cheese, 1 tbsp of the thyme leaves, some freshly ground black pepper and 1 tsp salt. Blitz again briefly to combine. Add 2-3 tbsp cold water, and pulse again until it comes together into a dough. If you don’t have a food processor, do this in a bowl – rub the flour into the butter first, then stir in the remaining ingredients with a knife. Wrap and chill for at least 40 mins.

Meanwhile, heat the 25g butter and the olive oil in a large frying pan over a low-medium heat, and cook the onions with a pinch of salt for 40-50 mins, stirring often, until sticky, golden and very soft when pressed with the back of a spoon. If they start to catch, reduce the heat further and add a splash of water. Be patient, as they will take a while to caramelise, but keep your eye on the pan so they don’t burn.

Stir in the vinegar, sugar and the anchovies. Keep stirring until the vinegar has evaporated, and the anchovies have dissolved into the onions. Remove from the heat.