Zucchini Tart

Ingredients

• 2 prepared 9-inch refrigerated pie crusts
• 2 tablespoons extra virgin olive oil
• 2 large onions, ½-inch dice
• 1 medium green zucchini, ½-inch dice
• 1 medium yellow squash, ½-inch dice
• ½ teaspoon salt
• ¼ teaspoon coarse ground pepper
• ½ cup grated Gruyère cheese, plus ⅛ cup for topping
• 1 large whole egg plus 1 large egg yolk
• 2 sprigs thyme leaves, chopped
• ¼ cup heavy cream
• 1 medium green zucchini, cut into ⅛-inch slices
• 1 medium yellow squash, cut into ⅛-inch slices