This tart is the perfect pairing with a spring mix salad for a light dinner or as a side dish for a charred grilled steak with asparagus. It's the perfect combination of favors. Sweet deep caramel onions, creamy potatoes and gruyere held together by a divinely buttery crust. I played around with this recipe a bit because I love tarts, but am not a huge fan of quiche, unless it's filled with delicious add ins and not so eggy. That's what's perfect about this tart. Where as many recipes call for multiple eggs to hold the tart together, this one only has one, leaving a tart that is full of flavor and still holds together well. The tart would freeze beautifully for a quick weeknight meal. Enjoy! Caramelized Onion and Potato Tart Pie Crust 1 1/2 c flour 3/4 teaspoon salt 1 stick of cold butter 4 tablespoons ice water 1 teaspoon vinegar 1 egg white Tart Olive oil Butter 1 1/2 lbs. Onions, diced 3 medium Red potatoes, cubed small 1 Egg 1 egg yolk 1/2c Sour Cream 3/4 c Gruyere Cheese, shredded Rosemary and/or thyme Salt and pepper Bay leaf To make the Pie Crust Preheat the oven to 425 degrees Mix the flour and salt. Cut the butter in until it resembles wet sand. Add the vinegar. Add the water one tablespoon at a time, just until the dough holds together. Form into a flat disk and refrigerate for 20 minutes. Remove from the fridge and roll out. Fit the dough in a round tart pan. Trim the edges and prick with a fork. Brush the bottom with egg white and make for 12 minutes. For the Tart filling Oven temperature 375 Heat the olive oil and butter over medium heat. Add the onions and season with salt. This will draw out the moisture and prevent them from browning, which you do not want. Cook the onions over medium-low heat until they are golden brown. Remove from the heat and cool. While the onions are cooking, cube the potatoes and par-boil them in water seasoned with salt and bay leaf. Drain the potatoes and let cool. In a large bowl mix the sour cream, egg and all but 1/4 cup of the cheese. Add the herbs and season with salt and pepper. Fold in the onions and potatoes gently so the potatoes don't break apart. Pour into the ore-baked tart shell. Top with the remaining gruyere and bake for 25-30 minutes until the top is golden brown and bubbling. Let the tart rest for 15 minutes before slicing.