Rustic Cherry Tomato Tart with Caramelized Onions
Ingredients
Method
- Place a large skillet over medium-low heat. Melt the butter, then add the onions, salt, and pepper. Cook for 20 to 25 minutes, stirring occasionally, until the onions are soft and deeply golden brown. Remove from the heat and set aside.
- Preheat the oven to 450 degrees Fahrenheit.
- Press both pie crusts together into one ball, knead briefly to combine, then roll out into one large, thin sheet. Lay the dough into a shallow quarter sheet pan, or cut in half and press into two standard pie pans. Sprinkle the fontina, Parmesan, and Gruyere evenly over the dough, then scatter the caramelized onions on top, and finish with the cherry tomatoes.
- Whisk the egg and milk together in a small bowl, then brush the mixture over the exposed crust edges. Bake for 20 to 22 minutes, checking often so the crust does not burn. The tomatoes should start to burst and develop some dark, roasted spots, while the crust turns deep golden brown. If the edges brown too quickly, lower the oven to 425 degrees Fahrenheit.
- Let the tart rest for 5 minutes out of the oven. Sprinkle the basil ribbons generously over the top, cut into squares, and serve warm or at room temperature.
Nutrition
Notes
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Let us know how it was!Why This Recipe Works
I still remember the first tart I tried to pull off. It was August, the kitchen was sweltering, and I’d spent an hour carefully arranging gorgeous heirloom slices only to end up with a pale, leaky, soggy-bottomed mess. Honestly? I almost gave up on tomato tart entirely.
This easy tomato tart is the recipe that changed my mind. It hits everything you want from a summer tart: sweet caramelized onions, three melty cheeses, and blistered cherry tomatoes piled onto a flaky, golden store-bought crust. And it comes together in about 45 minutes, mostly hands-off.
The trick is the method. Small whole cherry tomatoes, a generous layer of cheese, and a hot oven that does the heavy lifting. No blind baking, no fussy pastry work. If you can caramelize an onion and roll out a pie crust, you can absolutely pull this off on a busy weeknight.
This savory tomato tart has become my answer to everything lately. Weekend brunch, a light summer dinner, a potluck where everyone asks for the recipe. It’s rustic, forgiving, and genuinely gorgeous on the table. Let me walk you through it.
Ingredients & Substitutions
Here’s what you’ll need for this tomato tart recipe. Most of it is probably already in your kitchen.
- Butter and yellow onions: The base of everything. Halved and thinly sliced, then caramelized low and slow until deep golden brown. This step can’t be rushed.
- Store-bought pie crusts: Two of them, pressed together and rolled into one big thin sheet. Or use one generous homemade crust if you prefer.
- Fontina, Parmesan, and Gruyère: The three-cheese trio. Fontina brings the melty stretch, Parmesan adds a salty bite, and Gruyère gives that nutty depth. Any good melting cheese works, so feel free to swap in Monterey Jack, provolone, mozzarella, or mild cheddar.
- Cherry tomatoes, red and/or yellow: Keep them whole. They burst beautifully in the heat and look incredible scattered across the top.
- Egg and milk: Whisked together for the egg wash that gives the crust that glossy, deep golden finish.
- Fresh basil: Cut into ribbons (chiffonade) and scattered on top after baking.
August is prime farmer’s market season for summer tomatoes, by the way. Grab whatever looks most vivid. The red and yellow mix makes this tart look like it belongs on a magazine cover.
How to Make This Tomato Tart
The whole thing moves quickly once the onions are done. I’ve broken it into four stages so you know exactly what success looks like at every point.
Stage 1: Caramelize the onions
Melt the butter in a large skillet over medium-low heat, then add the sliced onions with a pinch of salt and pepper. Now the hard part: leave them alone. Let them cook for 20 to 25 minutes, stirring occasionally, until they turn soft, jammy, and deeply golden brown. The smell alone is worth it. Low and slow is the whole game here.
Stage 2: Roll out the crust
While the onions work their magic, press both pie crusts together into one ball, knead briefly to combine, and roll out a large, thin sheet. Lay it into a shallow quarter sheet pan (or cut it in half and press into two standard pie pans). Shallow is the keyword. A deep pan traps steam and gives you a doughy bottom, which is exactly what we’re trying to avoid. It’s the simplest trick I know for keeping a crisp-bottomed tomato tart.
Stage 3: Layer it up
Sprinkle the fontina, Parmesan, and Gruyère evenly over the dough. Scatter the caramelized onions on top, then finish with the cherry tomatoes, whole and washed. And please, dry those tomatoes thoroughly first. Moisture at the bottom of a tart is the number one cause of a soggy crust, and we’re not about that life today.
Stage 4: Egg wash, bake, and rest
Whisk the egg and milk together and brush the mixture over the exposed crust edges. That’s the secret to that glossy, golden frame. Bake at 450°F for 20 to 22 minutes, checking often. You want the tomatoes to start bursting and developing dark roasted spots, while the crust turns deep golden brown. If the edges brown too quickly, drop the oven to 425°F.
Let your tomato tart rest for 5 minutes before scattering fresh basil ribbons over the top. Cut into clean squares with a hot, sharp knife and serve. A few minutes out of the oven, any liquid from the tomatoes settles right back into the tart, so don’t panic if it looks a little juicy at first.
Why This Works
No blind baking needed here: the cheese layer melts into a protective seal between the dough and the juicy tomatoes. Combined with a hot 450°F oven and thoroughly dried cherry tomatoes, it’s a fuss-free path to a crisp, crackly crust.
Pro Tips & Troubleshooting
Even a forgiving recipe can throw a curveball. Here are the common mistakes I’ve made (and seen others make) so you don’t have to.
- ❌ Mistake: Using a deep pan.
✅ Fix: Switch to a shallow quarter sheet pan or standard pie pans. Deep dishes trap steam and give you a pale, soggy base. - ❌ Mistake: Rushing the onions.
✅ Fix: Cranking the heat gives you burned, bitter onions instead of sweet caramelized ones. Keep it at medium-low for the full 20 to 25 minutes. - ❌ Mistake: Skipping the tomato drying.
✅ Fix: Wet cherry tomatoes dump moisture into the tart while it bakes. Wash them, dry them thoroughly, then proceed. - ❌ Mistake: Letting the crust over-brown before the tomatoes finish.
✅ Fix: Tent the tart loosely with foil or lower the oven to 425°F. Those tomatoes need the extra few minutes.
If you’re wondering how to keep a tomato tart from getting soggy, the trifecta is simple: dry tomatoes, a cheese layer acting as a barrier, and a hot oven. This recipe checks all three boxes.
Tomato Tart Variations
This tomato tart recipe is endlessly adaptable. Here are my favorite ways to switch it up depending on what’s in the fridge.
- Change the cheese: Provolone, mozzarella, mild cheddar, or even a soft goat cheese on top of the fontina. Just pick something that melts well and you’re good.
- Swap the herbs: Basil is classic, but fresh thyme, chives, parsley, or finely chopped rosemary all work beautifully. Add them right before serving so they stay bright.
- Go gluten-free: A store-bought gluten-free pie crust is an easy swap, and nobody at the table will know the difference.
- Make it a galette: Roll the dough to roughly 14 inches, leave a 2-inch border, and fold the edges up around the filling for a free-form French tomato tart.
- Go full tarte à la tomate: The traditional French version sometimes spreads a thin layer of Dijon mustard on the crust or adds a couple of anchovies underneath the cheese. Totally optional, but delicious if you like the vibe.
What to Serve with Tomato Tart
This savory tomato tart is honestly a full meal on its own, but it plays beautifully with others. For a summer lunch, pair it with a crisp green salad dressed with a simple vinaigrette. It’s also wonderful alongside grilled chicken or fish if you’re feeding a crowd.
Because it tastes great warm or at room temperature, it’s perfect for brunch tables, picnics, and potlucks. Cut it in squares, not wedges, and watch it disappear. Honestly, I’ve eaten it cold from the fridge the next morning with zero regrets.
Storage & Reheating
This tomato tart is at its very best the day it’s made. The crust stays crackly, the tomatoes are at peak burstiness, and the basil is bright and fresh.
That said, leftovers keep in the refrigerator for up to 2 days. Store them in an airtight container and reheat at 350°F to bring the crisp back. Please don’t microwave a tomato tart, it turns the crust into a sad, spongy mess.
Want to get ahead? Caramelize the onions a day in advance and refrigerate them. Assembly the next day takes about 10 minutes. That’s my favorite little make-ahead trick for this tomato tart when I’m hosting.
Frequently Asked Questions
There’s nothing quite like pulling a golden tomato tart out of the oven on a warm August evening. The blistered cherry tomatoes, the jammy onions, that crackly crust, the sharp little ribbons of basil. It’s the recipe I make every single summer, and it never gets old.
If you make this tomato tart, I’d love to hear about it. And if you’re looking for more summer-friendly inspiration, come find me on Pinterest, I’m always pinning seasonal favorites just like this one. Follow along here.
Source: Learn More About This Dish
Do I bake the crust before filling it or do I fill it raw?
In this tomato tart recipe, you fill the crust raw. The cheese melts into a protective barrier that keeps the dough crisp while the tomatoes blister. No blind baking needed, which saves you a solid 20 minutes.
Can I use a sheet of puff pastry instead of a store-bought pie crust?
Yes, a puff pastry tomato tart works too. Roll the sheet out slightly and trim it to fit your pan. Just know the bake time can shift a little, since puff pastry is thinner and more delicate than the sturdy pie crust this recipe was built around.
What temperature is this tart best served at?
Warm or at room temperature, honestly. The flavor is incredible either way. Just give it 5 minutes out of the oven so the juices settle, then slice into squares. At a summer table, room temperature is genuinely perfect.
How can I tell if a tomato is ripe?
For this tart, pick cherry tomatoes that feel heavy for their size, smell sweet at the stem, and have vivid, even color. A ripe tomato gives slightly to gentle pressure without feeling mushy. Good ones make the whole tart sing.
Can I use other cheeses in this tart?
Absolutely. This tomato tart is super flexible with cheese. Fontina, Monterey Jack, provolone, mozzarella, Swiss, or mild cheddar all melt beautifully. Just avoid anything overly dry, since you want that creamy, stretchy layer under the tomatoes.