Gluten Free and Dairy Free French Onion Soup Puff Pastry Bites

1 sweet or yellow onion 2 tbsp olive oil or dairy free butter Splash Balsamic vinegar Salt, pepper to taste Gluten free and dairy free puff pastry Dairy free mozzarella cheese 1 egg for egg wash Peel and cut onions in half from root to stem, and slice into thin strips In a pan over […]