My friend Priya is a fantastic baker. I watched her assemble a gorgeous onion tart at a dinner party recently. It was in the oven baking while I gorged myself on the other delicious offerings, but I willed myself to accept a slice of the tart once it was ready. And am I glad that I did because it was so GOOD! I ate more than the tiny slice I set out for, and I craved it for weeks after. I had to get myself another fix before this summer’s beautiful tomatoes disappeared, and my attempt at her tart turned out great. Its flavors are balanced and interesting, and its visual appeal is undeniable.
To make this tart, parbake a pie crust in a tart pan with a removable bottom. You can read my directions for making, shaping, and parbaking a pie crust here. While the crust is cooking, get the tart’s other ingredients ready. Slice 2 onions, and heat 1 tablespoon of oil in a pan. Add the onions, along with a few sprigs of thyme, into the pan. Season the onions with salt and pepper, and sweat them, stirring occasionally, until they just begin to caramelize, about 15 minutes. Once the onions have started to pick up some color, they should have sweetened considerably. Set them aside to cool.
When the tart is cool enough to handle, spread the bottom with Dijon mustard. I used 2 tablespoons of Dijon, and I could definitely taste the mustard in the finished product. The slight spice and vinegary tang was a welcome counterbalance to the sweeter onions and tomatoes, but if you’re not a huge fan of Dijon mustard, then you might was to spread the crust with less… maybe half or two-thirds the amount.
Spread your slightly caramelized onions in an even layer on top of the mustard. Season the onions with a bit more salt and pepper.
Top the onions with a layer of shredded fontina cheese. I think gruyère cheese would work well here, so I’ll probably try that next time.
Halve some of the prettiest cherry tomatoes you can find, and arrange them cut-side down on top of the cheese so that the tart is completely covered. At this point, Priya also crumbled some goat cheese onto the tart between the onions, but you know how I feel about goat cheese…
Bake the tart in a 400º F oven until the tomatoes and cheese begin to brown, about 20-30 minutes. Once the tart is cool enough to handle, you can pop the sides off of the tart pan and slice it to serve. I ate this tart for breakfast, lunch, dinner, and a snack, and it always satisfied. Love it!
- Pie crust– 1
- Onions- 2
- Salt and pepper
- Dijon mustard- ~2 tablespoons
- Fontina cheese- ~1.5 cups, shredded
- Cherry tomatoes