Gooey, sweet-sour, silky-soft onion on a crisp puff pastry base topped with salty molten blue cheese, is a superb combination. Make these lovely tarts as a starter or light supper with salad. Highly recommended.
Prep: 30 min
Cook: 40 min
3 large onions
3 tbsp olive oil
1 tsp dark brown sugar
½ (half) tbsp balsamic vinegar, preferably Belazu
320g ready-rolled puff pastry
1 egg yolk
100g Roquefort or other blue cheese
Heat the oven to 200C/gas mark 6. Quarter then peel the onions. Slice thinly across the quarters. Heat 3 tbsp oil in a spacious frying/sauté pan over a high flame and toss constantly for 5 minutes, stir-frying until wilted and glistening. Add ½ tsp salt, stir-fry for a further 5 minutes, reduce the heat and cook gently, stirring often until sloppy, wilted and tender. Stir in the sugar, when melted add the vinegar. Cook for a couple of minutes then spread on a plate to cool. Unfurl the pastry and slice through the width into 4 equal oblongs. Halve across the pieces. Butter a parchment-lined baking sheet and carefully transfer the pastries with space between. Etch a 1cm border, paint with beaten egg yolk then prick the entirety inside the border with a fork. Spread onion within the border. Cut chunks of cheese over the onion. Bake for 15 minutes or until the border is puffed and golden, the cheese molten. Cool slightly on a cake rack before serving.