{The Saturday Post} Cauliflower and Caramelized Onion Tart

What do you make to celebrate an upcoming marriage, that will cater to a groom’s cravings and a bride’s desire to fit into her wedding dress in six months? This was the question I asked myself when planning the menu for a little engagement party we had a couple of weeks ago.

Tarts immediately came to mine. They’re light, but depending on which ingredients you choose to fill it, hearty enough to feel like a meal. I’ve made tomato tarts and ricotta and zucchini tarts with much success, but wanted to try something new this time. As usual, Deb reads my mind, and posted a delicious, party-worthy tart just days before I started planning.

The mustard, in fact, was one of my favorite parts of this dish. I love caramelized onions (here's a great way to use them!), roasted caluliflower any time, and cheese. I knew this was a win-win situation for everyone. But as delicious as all those individual ingredients are, the mustard, with its barely-there tartness was a subtle, unifying ingredient that no one could really put their finger on but truly enhanced every bite. Mmm. My mouth is watering a little bit just describing it.


{printable recipe}

Recipe adapted from Smitten Kitchen, via Bon Appetit

Yields 6 to 8 servings

This is a great make-ahead dish. The tart shell can be made the day before and kept in the fridge, and the same goes for the cauliflower and onions. All you'll need to do on party day is roll out the tart shell, assemble the filling, and bake.


1 small head of cauliflower (about 1 pound), cut into 1-inch florets

3 1/2 tablespoons olive oil

1 tart shell (recipe below)

1 large onion, halved lengthwise and thinly sliced

1 1/2 tablespoons Dijon mustard

2 large eggs

1 (7- to 8- ounce) container mascarpone cheese

1/2 cup whipping cream

1/4 teaspoon ground black pepper

1 cup grated Gruyère cheese

1/3 cup Parmesan cheese


Position rack in center of oven and preheat oven to 425°F. Toss cauliflower with 2 tablespoons olive oil in a large bowl. Spread on a rimmed baking sheet, sprinkle with salt and pepper and roast for 30 minutes, turning the florets over half way through. Reduce temperature to 350°F.

While the cauliflower cooks, lightly flour a work surface and roll out the tart shell using a rolling pin. I found mine to be quite firm from its time in the fridge, so take the dough out at least 30 minutes before you plan to use it so it will be easier to roll. Gently press the dough into the tart pan and trim off any excess.

Heat remaining 1 1/2 tablespoon olive oil in a heavy large skillet over medium-low heat. Add onion, sprinkle with salt and pepper and cook until onion is a deep golden brown, stirring occasionally. Set aside.

Using a small icing spatula or knife, spread the bottom and sides of crust with mustard. Spread onion over crust. Arrange cauliflower over the onion. Set the tart on a rimmed baking sheet. Whisk eggs, mascarpone, cream and pepper in a medium bowl. Stir in Gruyère. Pour mixture over filling in tart pan and sprinkle with Parmesan. Bake until tart is golden and center is set, about 40 minutes. Transfer to rack and cool 15 minutes before serving.


Recipe adapted from Smitten Kitchen, via Le Pain Quotidien


1 1/4 cups flour

1 tablespoon plus 2 teaspoons cornstarch

1/4 teaspoon salt

6 tablespoons butter, diced

1 egg


In a food processor, combine the flour, cornstarch and one-fourth teaspoon salt. Add the butter, then pulse several times to incorporate. The butter should be small, like tiny peas. Add the egg and blend until a dough forms. It will seem like there isn't enough moisture at first, but after about 10 seconds the mixture will suddenly come together. Chill for 30 minutes.

On a lightly floured surface, roll the dough out to a 12-inch circle. Place the dough in a 9-inch pie plate or tart pan and press to remove any air bubbles. Crimp the edges, and proceed with a filling of your choice, no parbaking required.