Tomato Tarte Tatin Recipe

INGREDIENTS

• 2 medium yellow onions, chopped
• 2 tablespoons extra-virgin olive oil or clarified butter
• 1 1/2 pounds / 24 oz small tomatoes (here it's a mix of heirloom cherry & early girls)
• scant 1/2 teaspoon fine grain sea salt
• 2 teaspoons balsamic vinegar
• a bit of flour
• zest of one lemon
• 1 pie crust, this rye crust is my go-to
• 1 egg whisked with a tablespoon of water