This Onion Tarte Tatin is a fun way to make an onion tart, applying the traditional apple tarte tatin technique to onions. The idea is to cook the onions in a skillet on low heat, with the sweet flavors of honey and cinnamon, along with nutmeg, pepper, and balsamic vinegar to top it off. Then, the onions are covered with puff pastry, and baked in the oven, The result is a sweet upside-down onion tart.
All ingredients are easy to find with the exception of puff pastry (depending on where you live). Whole Foods generally carries high-quality puff pastry. You can also usually find the pepperidge farm or wewalka brand in local grocery stores. Puff pastry can also be ordered online.
Please note, this recipe is for a small 9‑inch tart. If your pan is bigger, adjust ingredients accordingly.
Cut the onion in 4 and slice it. See picture. Then put the onion slices for about a minute in boiling water, then drain, and put aside.
Generously sprinkle the onions with pepper, cinnamon and nutmeg. In a skillet, on low to medium-heat, place 2 tbsp butter, the onions with the spices and the honey. Cover and let it cook for 25 minutes on low-medium heat. Then, uncover and add a drizzle of balsamic vinegar to the mix. Continue cooking for about 2 minutes in the uncovered skillet.
Preheat oven to 350 degrees Fahrenheit. Butter or coat with oil a 9‑inch round dish or pan. Place the drained onions in the dish.
Unroll your puff pastry and place it over the onions. Push down on the sides to ensure the puff pastry is all around the onions (you want to make sure the onions won’t fall out once you turn the tart upside-down).
Bake in oven for 30 minutes. Take it out of the oven and set it aside for a minute or two. Place a plate on top of the crust, and turn the dish upside-down so the tart directly falls onto your plate. Voilà! Enjoy warm.