Pumpkin, Feta and Caramelised Onion Tart

Name: Pumpkin, Feta and Caramelised Onion Tart
Prep time: 15 min
Cook time: 1 h 10 min
Total time: 1 h 25 min
Cuisine: European, Mediterranean, Greek
Ingredients: 8 sheets filo pastry; 60 g unsalted butter, melted; 170 g red onions, quartered; 10 g olive oil; 10 g balsamic vinegar; 10 g brown sugar; 1 garlic clove; 3 pinches fine sea salt; 550 g pumpkin flesh, diced (1 cm); 15 g honey; 2 pinches ground black pepper, or to taste; 200 g fresh baby spinach; 40 g whipping cream; 2 large eggs; 15 cherry tomatoes, halved; 200 g feta cheese, diced (1 cm)