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  • Writer's pictureKaren Calderon-Schweitzer

Caramelized Onion and Mushroom Tart

I just absolutely love Thanksgiving! It kicks off the Holiday Season with tradition, family, friends and tantalizing dishes expected of the holiday. Although I have a traditional menu that includes the "must haves" for the holiday, I love adding a little something new to our menu which always brings an element of surprise to the table.

This flavorful and simple Caramelized Onion and Mushroom Tart from my Passionista Kitchen is a perfect addition to your Thanksgiving menu. I love how the slight sweetness of the caramelized onions and the earthy flavor from the mushrooms play against the creamy and nutty flavor of the Gruyere cheese. It really is a simple dish to prepare and your family and guests will be delighted with this tart.

This delicious tart can also be served any day of the year and if I am making it for a weekday dinner, it really elevates the day to day dinner time. I love making the tart the star of the meal and serve it with a simple green salad with a tangy balsamic vinaigrette or ripe cherry tomatoes topped with fresh basil, salt pepper and and olive oil.


• 1 refrigerated pie crust • 1 tablespoon Dijon mustard • 2 tablespoons butter, divided • 1 large red onion, sliced lengthwise • ½ teaspoon of sugar • 4 Sprigs of fresh thyme – separate leaves from stems • 4 ounces mushrooms sliced – I used cremini mushrooms but white mushrooms will work well too. • 2 large eggs • 3/4 cup half-and-half • 1 cup grated Gruyere cheese • 2 teaspoons of your favorite seasoned salt • 1 teaspoon of Worcestershire sauce • Salt and freshly cracked black pepper to taste

Preheat oven to 350°

Spray a 12 inch tart pan with non-stick baking spray and coat evenly. Roll out pie crust to fit in the tart pan and gently press into the sides. Coat the bottom surface with Dijon mustard. Bake in preheated oven for 10 minutes. Remove from the oven and let it cool to room temperature.

In a large skillet, over medium heat melt 1 tablespoon of butter. Add onions, sprinkle with 1 teaspoon of seasoned salt and thyme leaves. Increase heat to medium high and sauté for about 10 minutes. Sprinkle with ½ teaspoon of sugar and continue to sauté for about 5 minutes or until onions are caramelized. Set aside into a large bowl and let the onions cool down.

In the same skillet, over medium-heat melt the last tablespoon of butter and add mushrooms. Increase heat to medium-high and sauté mushrooms for about 7 minutes. Add one teaspoon of seasoned salt and Worcestershire sauce. Continue to sauté for another 5 minutes and set aside with onions to cool down. In a separate bowl add eggs, half-and-half and beat until combined.

When onions and mushrooms come to room temperature add egg mixture and half of the cheese. Combine well and add salt and freshly cracked pepper to taste. Pour egg mixture into tart and sprinkle with remaining cheese.

Bake in preheated oven for about 40 minutes or until the tart is golden brown and the filling has set. Let it cool down before serving. Serve warm or at room temperature. Enjoy while warm.


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