Ingredients 

• 1 large sheet of ready-rolled puff pastry
• 2 tbsp olive oil
• 3 large red onions
• Maldon Sea Salt Flakes
• Cracked black pepper
• 1 tbsp Billington’s Golden Caster Sugar
• 2 tbsp balsamic vinegar
• Fresh thyme sprigs

Method

1. Preheat oven to 175C.
2. Peel onions and cut into thick rounds. Coat a heavy based ovenproof frying pan or skillet pan with olive oil so that the bottom is covered with a thin layer and heat over medium-high heat. Add onions to the pan and season with a pinch of salt and pepper. Reduce heat to low and cook for 5 minutes per side.
3. Arrange onions in an even layer in the pan. Mix sugar and balsamic vinegar together and pour over the onions, then remove from heat.
4. Cut pastry into a circle to fit the pan, allowing a little extra to tuck into the sides of the pan. Place pastry on top of the onions, ensuring that they are covered and tuck into the sides of the pan. Use a fork to poke a few holes in the pastry and place in the oven to cook for 20-25 minutes or until the pastry is golden brown.
5. Remove from oven and allow to sit for 5 to 10 minutes, then place a serving plate over the frying pan and quickly flip so that the onions are on top.
6. Garnish with thyme sprigs and serve.