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Course Appetizer, Breakfast, Main Course, Side Dish
Cuisine American
Servings 8
Calories 147 kcal


To Assemble The Tart

  • 1 sheet store bought puff pastry thawed, rolled out, and baked.
  • 2 oz goat cheese
  • pepper
  • salt

For The Caramelized Onions

  • 1 1/2 - 2 medium-sized red or yellow onions, evenly sliced 1/8 inch thick If you slice them too thin, the onions will burn.
  • 2 - 3 T water, stock, or wine To deglaze the pan after caramelizing the onions.
  • 2 T butter
  • 1 T olive oil

For The Seared Mushrooms

  • 3 - 4 c chopped mushrooms Use any kind you like.
  • 4 - 6 sprigs fresh thyme
  • 2 cloves crushed garlic These will be removed from the mushrooms before assembling the tart.
  • 2 T butter
  • 2 handfuls fresh spinach The spinach is optional, use more, less, or none.
  • salt
  • pepper


For The Puff Pastry

  • Preheat oven to 400.
  • Thaw one sheet of a 1.1 pound box of puff pastry for 40 minutes. On a medium-floured surface roll out the sheet into a 16 x 10-inch rectangle and place it on an ungreased cookie sheet. Score a one-inch rim around all four sides. If you cut through the pastry sheet the rim and bottom will separate during cooking. Poke the tines of a fork through the bottom of the pastry (inside the scored rim) at 1/2 inch intervals. This prevents the bottom from puffing up. Bake 15 minutes at 400, rotate the cookie sheet 180 degrees at the 7-minute mark.
  • Reduce the oven temperature to 350 to prepare for baking the tart or turn the oven off until ready to cook the tart. 

For The Caramelized Onions

  • Put 2 T butter and 1 T olive oil in a 12-inch skillet and heat over medium-low heat. Put the onions in the skillet and stir them around to evenly coat with the butter/oil mixture. Keep the heat low and cook the onions for a solid 40 - 50 minutes. Set a timer. The onions will reduce in volume considerably. Around the 20 minute mark, they start getting a yummy brown color. Be patient. Stir occasionally. Once the onions are cooked, deglaze the pan with a little water, wine, or stock. Get all the brown bits off the bottom of the pan. Transfer the onions and deglazing liquid to a medium bowl. 

For The Seared Mushrooms And Spinach

  • Heat 2 T butter in a skillet. When it is foaming, add the mushrooms and don't touch them for 3 - 5 minutes. Add 2 crushed garlic cloves, 2 sprigs fresh thyme, and sprinkle with salt and pepper. Let cook until the mushrooms are browned around the edges, then stir.
  • Add 2 handfuls of fresh spinach. Stir to combine and cook until the spinach is bright green. (Less than 2 minutes if your pan is hot.) Discard the thyme and garlic. Transfer everything to the bowl with the onions. If there is liquid in the bottom of the bowl, drain the mixture before spreading it on the puff pastry.

Assemble The Tart

  • Spread the onion, mushroom, and spinach mixture over the cooked puff pastry. Sprinkle with 2 oz goat cheese and 2 - 3 new sprigs fresh thyme. Salt and pepper to taste.
  • Bake at 350 for 12 - 15 minutes until heated through.