Caramelized onion tarts - Krinos

Ingredients

• Pastry dough
• • 250 g self-rising flour
• • 130 g butter
• • 100 g greek yogurt
• • 1 egg
• • Salt & pepper
• Filling
• • 500 g onions, cut into rings
• • 20 ml olive oil
• • 3 tbsp brown sugar
• • 3 tbsp balsamic vinegar
• • 20 g butter
• • 3 tbsp fresh thyme, chopped
• • 100 g emmental cheese, grated
• • 50 g parmesan cheese, grated