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Rustic Onion Tart

Rustic Onion Tart
  • Category

    Breakfast and Brunch

  • Cusine

    American

What do you need?
How to make?

Ingredients

1 recipe for butter sour cream pastry dough* or 1 packaged, flat pie crust

3 medium sized red and/or yellow onions

2 tablespoons extra virgin olive oil

1 tablespoon butter

Salt

1 teaspoon balsamic vinegar

1/2 teaspoon fresh thyme, chopped, or 1/4 teaspoon dried thyme

3/4 cup roughly grated Gruyère Swiss cheese

1 1/4 cup all purpose flour

1 teaspoon salt

5 ounces of butter , cubed

1/4 cup sour cream

Directions

If you are making a crust from scratch, prepare the dough and let it chill in the refrigerator while you are cooking the onions. To prepare the dough, whisk the flour and salt together in a large bowl. Cut the butter into the flour with your hands or with a pastry cutter, until the mixture resembles a coarse meal. Add the sour cream and use a fork to incorporate it into the dough. Gather the dough into a ball and shape it into a disk. Wrap it with plastic wrap and chill for at least an hour. Peel and slice the onions, lengthwise from stem to root.

Heat olive oil and butter in a large, heavy-bottomed sauté pan on medium heat. Once the butter has melted, add the onions and sprinkle a little salt over them. Cook, stirring occasionally for 10 minutes, until the onions have softened and are translucent. Reduce the heat to medium low and cook for an additional 40 minutes, stirring occasionally, until the onions are well browned. Add balsamic vinegar and cook for 10 minutes more, until onions are completely caramelized. Remove from heat.

Preheat the oven to 450 degrees F. Remove the dough from the refrigerator and let stand for 5 minutes before rolling it out. Roll out the dough on a lightly floured surface to a 13-inch diameter. Transfer the crust dough to a cookie sheet lined with parchment paper.

Place all but a couple tablespoons of the cheese in the center of the dough. Spread to within 1 1/2 inches from the edges. Add the caramelized onions, layering them on top of the cheese. Sprinkle with thyme.

Fold the edges of the crust dough over so that a small circle of onion is still showing in the centre of the tart. Sprinkle the remaining cheese over the top of the tart.

Place in the oven on the middle rack. Bake for 10 minutes at 450 degrees F. Reduce the heat to 350 degrees F and bake for an additional 20-25 minutes, until the crust is golden brown. Remove from oven and let sit for 10 minutes before serving.