I used to not like onions. I know what you’re thinking, who was I? And I totally agree. Who doesn’t like onions? First of all, they’re on everything. Second of all, they’re so delicious!! The first time I consciously had caramelized onions (and also watched someone make them) was back when Dave and I first started dating, and it was actually an important day in our relationship. Perhaps this is where my new love for onions comes from! There are so many great things you can do with them, but often they are an add-on to a dish, and not the dish themselves. So when I saw this tart, I just had to try it. And oh my god, it is amazing. The combination of balsamic vinegar and onions is a truly good partnership.
This dish is the perfect appetizer because it’s surprisingly light! It’s also a great dish to make while making other things, because while you don’t actually have to do a ton of work, the onions do have to sit on the stove for an hour to an hour and half. So it’s perfect to do while you’re preparing something else.
Recipe adapted from here.
2 cups flour
1/2 teaspoon mustard
Pinch cayenne pepper
1 stick butter
4 tablespoons cold water
2 tablespoons butter
4 white or yellow onions, sliced thinly
1/3 cup balsamic vinegar
1/4 cup brown sugar
Salt and pepper
Stem of fresh thyme
5 oz. soft goat cheese
2 tablespoons fresh thyme leaves
1. The filling will take much longer to cook, so start with this. Melt the butter in a large frying pan. Once melted add the onions, salt, pepper, and thyme. Cook, stirring regularly, until the onions are soft and translucent, about 30 minutes. Be careful not to brown them.
2. Add the sugar and balsamic vinegar and continue cooking until almost all the liquid has absorbed. This took about 45 minutes to an hour. Try not to rush this. The longer you cook the onions, the more delicious they are. Once done, remove the fresh thyme.
3. While the onions continue to cook, prepare the crust. In a food processor mix the flour, salt, mustard, pepper, and butter until it turns into a crumbly texture. Add the cold water and pulse a few times, just until the dough comes into a ball (mine was still pretty crumbly and that’s ok). Wrap the ball in plastic wrap and chill in the fridge for 15 minutes.
4. Preheat the oven to 375 degrees. Prepare a tart pan (or pie pan if that’s all you have) by buttering the bottom and sides. Pour the dough into the pan and press evenly into the bottom. On top of this, place a layer of tinfoil and fill the foil with something heavy. If you have “baking beans” that’s great. If not, you can use something else. I had some dried beans that I used. Worst case scenario you could also do without anything. Bake the crust for 15 minutes, just to set the dough. Remove the beans and foil and bake for another 10 minutes or so, until the crust starts to brown slightly.
5. Add the onion mixture to the warm crust, and top with crumbled goat cheese. Reduce the oven temperature to 350 degrees and bake for an additional 15-20 minutes. Note: I waited in between steps 4 and 5 so that I could do step 5 right before we were ready to eat the tart.