Rustic Caramelized Onion Tart

I must preface this recipe with a warning: do not ever make it for another person. If you do, they will beg you on a very regular basis to make it for them again. It’s delicious and easy enough that you’ll do it.
I love a lot of food, so rarely will I insist that you make something right this instant, especially if it’s summer and it involves turning the oven on. But you need this. If you love caramelized onions even a little, you need this. If you love cheese even a little, you need this. If you love flaky, buttery pie crust, you need this. If you love all those things, you should already be at the grocery store.
I think my favorite thing about this is how perfectly everything comes together: the incredible dark sweetness of the onions, the salty tang of the cheese, the pure fatty deliciousness of the butter, and the freshness of the thyme just work. Perfectly. Plus, onions are totally a vegetable, so they cancel out the cheese. This is a fact.
Another bonus is that it looks pretty, so it’s great for serving at parties if you cut it into smaller wedges. Personally, I like to eat half of it for dinner. Like I said, onions = vegetable = health.

Rustic Caramelized Onion Tart (adapted slightly from Cooking Light)
1 pre-made refrigerated pie crust (I used Pillsbury, but feel free to make one yourself)
1 medium yellow onion, cut in half and sliced thin
1 medium red onion, cut in half and sliced thin
2 tablespoons fresh thyme (pull a ton off the stems and measure–it doesn’t have to be exact)
1 teaspoon sugar
generous 1/2 teaspoon salt
1/2 teaspoon pepper
1/3 cup non- or low-fat feta cheese, crumbled
1/3 cup shredded gruyere cheese (I use Trader Joe’s swiss and gruyere mix)
1 egg, beaten
olive oil

Preheat oven to 425 degrees and line a baking sheet with parchment paper. Set aside.

Heat a large, non-stick skillet over medium-high heat. Pour in enough oil to lightly coat the bottom of the skillet. When oil is hot, add sliced onions, thyme, salt, pepper, and sugar. Stir to mix seasoning in well and taste. It should not be as salty as you would like–the cheese will take care of that. Cook, stirring often, until onions soften and begin to caramelize, about 30 minutes. Remove from heat.

Unroll pie crust onto prepared baking sheet. Top with feta cheese, leaving a border of about 1 1/2 inches on all sides. Carefully pile onion mixture on top, staying within this border. Top with gruyere cheese. Take a small section of pie crust and begin to fold it up and over the filling, pleating as you go so it looks like the picture above. Brush crust liberally with beaten egg (if your kitchen can’t even fit a pastry brush, like mine, get creative with a spoon and your fingers). Bake for 25 minutes. Crust should be golden. Remove from oven and let cool at least ten minutes before slicing into four wedges. Count how many days until you use the second pie crust in the box to make another tart.