Fleeting Summer Tomato and Zucchini Tart | Ciao Italia

Ingredients

• 3 tablespoons olive oil plus extra to drizzle on top of tart
• 1 onion finely chopped
• 4 cups shredded zucchini
• Salt and pepper to taste
• 1 sheet prepared store-bought puff pastry, defrosted
• 2 tablespoons spicy mustard
• 2 cups grated sharp cheddar cheese
• 5 medium size tomatoes, cut into ¼-inch thick round slices
• 4 tablespoons fresh minced parsley