Red onion and parmesan tartlets - FAB

Ingredients

• 175g plain flour
• 85g chilled unsalted butter, cut into cubes
• 1 medium egg yolk
• 7 tsp cold water
• 10g unsalted butter
• 1 tbsp extra virgin olive oil
• 3 medium red onions, peeled and slice into small wedges
• 2tsp lemon juice
• 200ml tub low fat crème fraîche
• 1 tbsp fresh thyme leaves, chopped
• 55g freshly grated Parmesan
• Salt and freshly ground black pepper
• Extra thyme leaves, to garnish