Wow! This delicious little tart is so full of amazing flavors. Who can resist roasted cauliflower, caramelized onions and Gruyere cheese all topped with freshly grated Parmesan cheese to give it a nice golden brown crust on top? I sure can’t. My house smelled so amazing while this was baking. If you need to put this together at a later time you can certainly roast the cauliflower, caramelize the onions, and grate the cheeses an entire day ahead of time. Let’s get started.
Make sure that you use Mascarpone cheese. You could substitute regular cream cheese, however the Mascarpone is smoother and won’t clump like regular cream cheese. So do what you can to find it. It will be worth it in the end. I promise.
When caramelizing the onions just be sure to go slow. It takes time to get them to their perfect color. When you get ready to assemble the tart just brush the bottom and sides with the Dijon mustard, lay the onions on the bottom, top with the bite-sized roasted cauliflower. Beat your eggs first then add the mascarpone cheese, heavy cream, pepper, nutmeg and Gruyere cheese together in a medium sized bowl. Pour over onion/cauliflower mixture. Top with the Parmesan cheese. I pressed down on the cheese just a bit to make sure it formed a nice crust on top.
Bake for about 40 minutes. The tart will be nice and golden on top and the center will be set. Serve this as an appetizer, brunch item or for a meatless dinner served with a bright green salad. Whenever and however you serve it, it will be guaranteed to be a hit.
- 1 small head of cauliflower (about 1 pound), cored, cut into 1-inch florets
- 3 tablespoons olive oil
- 1 tablespoon butter
- 1 refrigerated pie crust
- 1 large onion, halved lengthwise, thinly sliced
- 1 table Dijon mustard
- 2 eggs
- 1 (7-8-ounce) container mascarpone cheese (Italian cream cheese) at room temperature
- ½ cup heavy cream
- ¼ teaspoon ground white pepper
- Pinch of nutmeg
- 1 cup grated Gruyere cheese
- ¾ cups grated Parmesan cheese
- Position rack in center of oven; preheat oven to 425 degrees F.
- Toss cauliflower with olive oil in a large bowl and season with salt. Spread on a large rimmed foil lined baking sheet. Roast for 15 minutes, then turn florets over. Continue roasting until tender, about 15 to 20 minutes longer.
- Cool cauliflower, then slice into small bite-sized pieces.
- Reduce oven temperature to 350 degrees F.
- Press pie crust into bottom and up sides of a 9-inch-diameter tart pan with removable bottom (I just used a regular pie pan). Line pie crust with foil; fill with pie weights (or raw beans) Bake crust 20 minutes.
- Remove foil and pie weights; bake until crust is golden, about 5 minutes, pressing crust with back of fork if bubbles form. Cool crust. Maintain oven temperature.
- Heat about 1 tablespoon olive oil and 1 tablespoon of butter in a large skillet over medium heat. Add onion; sprinkle with salt and pepper. Cook until onion is deep golden brown, stirring occasionally, about 40 minutes. Cool slightly.
- DO AHEAD Can be made 1 day ahead. Store crust at room temperature. Cover and chill cauliflower and onion separately.
- Brush bottom and sides of crust with mustard. Spread onion in crust. Arrange cauliflower evenly over. Set tart on rimmed baking sheet.
- Whisk eggs and next 4 ingredients in medium bowl. Stir in Gruyere cheese. Pour mixture over onions and cauliflower in tart pan; sprinkle with Parmesan.
- Bake until tart is golden and center is set, about 40 minutes.
- Transfer to rack; cool 15 minutes before serving. Serves 6.