Cauliflower and Caramelized Onion Tart Recipe
Introduction
This Cauliflower and Caramelized Onion Tart is a savory delight with a perfect balance of creamy cheese, tender roasted cauliflower, and sweet caramelized onions. Its flaky crust and aromatic truffle oil make it an impressive yet approachable dish for any occasion.
Ingredients
- 1 small head of cauliflower (about 1 pound), cored, cut into 1-inch florets
- 2 1/2 tablespoons olive oil, divided
- 1 tablespoon truffle oil
- 1 refrigerated pie crust
- 1 large onion, halved lengthwise, thinly sliced
- 1 tablespoon Dijon mustard
- 2 large eggs
- 1 (7- to 8-ounce) container mascarpone cheese
- 1/2 cup whipping cream
- 1/4 teaspoon ground white pepper
- Pinch of ground nutmeg
- 1 cup grated Gruyère cheese
- 3/4 cup grated Parmesan cheese
Instructions
- Step 1: Preheat the oven to 425°F and position a rack in the center. Toss the cauliflower florets with 1 tablespoon of olive oil, season with salt and pepper, and spread them out on a large rimmed baking sheet. Roast for 15 minutes, turn the florets over, and continue roasting until tender, about 25 minutes longer. Let cool, slice thinly, then drizzle with truffle oil and toss gently. Reduce the oven temperature to 350°F.
- Step 2: Press the refrigerated pie crust into a 9-inch tart pan with a removable bottom, making sure it covers the bottom and sides. Line the crust with foil and fill with pie weights. Bake for 20 minutes, then remove the foil and weights and bake an additional 5 minutes until golden, pressing the crust with the back of a fork if bubbles form. Allow the crust to cool.
- Step 3: In a heavy skillet over medium heat, heat the remaining 1 1/2 tablespoons of olive oil. Add the sliced onion, season with salt and pepper, and cook, stirring occasionally, until deep golden brown, about 40 minutes. Let the onions cool slightly.
- Step 4: Brush the bottom and sides of the cooled crust with Dijon mustard. Spread the caramelized onions evenly over the crust, then arrange the sliced cauliflower on top. In a bowl, whisk together the eggs, mascarpone cheese, whipping cream, white pepper, and nutmeg. Stir in the grated Gruyère cheese. Pour this mixture over the filling in the tart pan, then sprinkle with Parmesan cheese. Place the tart on a rimmed baking sheet and bake for about 40 minutes, until golden and the center is set. Let cool for 15 minutes before serving.
Tips & Variations
- Use a pre-made pie crust to save time or make your own for a buttery touch.
- For extra flavor, add fresh thyme or rosemary to the caramelized onions while cooking.
- Substitute Gruyère with fontina or sharp cheddar for a different cheese profile.
- Drizzle a little extra truffle oil over the tart just before serving for enhanced aroma.
Storage
Store leftovers in an airtight container in the refrigerator for up to 3 days. Reheat individual slices in the oven at 350°F until warmed through to maintain crispness. Avoid microwaving to keep the crust flaky.
How to Serve
Serve this delicious recipe with your favorite sides.
FAQs
Can I prepare this tart in advance?
Yes, the tart can be assembled a few hours ahead of time and refrigerated. Bake just before serving for the best texture and flavor.
Can I use a different vegetable instead of cauliflower?
Absolutely. Broccoli or asparagus can be great substitutes that pair well with the caramelized onions and cheese filling.
Print
Cauliflower and Caramelized Onion Tart Recipe
- Total Time: 1 hour 45 minutes
- Yield: 8 servings 1x
- Diet: Vegetarian
Description
A savory and elegant Cauliflower and Caramelized Onion Tart featuring tender roasted cauliflower, sweet caramelized onions, creamy mascarpone filling, and a blend of Gruyère and Parmesan cheeses in a flaky pie crust. Perfect as a sophisticated appetizer or a light main course.
Ingredients
Scale
Vegetables
- 1 small head of cauliflower (about 1 pound), cored, cut into 1-inch florets
- 1 large onion, halved lengthwise, thinly sliced
Oils & Fats
- 1/2 tablespoons olive oil, divided (1 tablespoon + 1 1/2 tablespoons)
- 1 tablespoon truffle oil
Dairy & Eggs
- 1 refrigerated pie crust
- 2 large eggs
- 1 (7- to 8-ounce) container mascarpone cheese (Italian cream cheese)
- 1/2 cup whipping cream
- 1 cup grated Gruyère cheese
- 3/4 cup grated Parmesan cheese
Condiments & Spices
- 1 tablespoon Dijon mustard
- 1/4 teaspoon ground white pepper
- Pinch of ground nutmeg
- Salt and pepper to taste
Instructions
- Roast Cauliflower: Preheat the oven to 425°F (220°C) and position the rack in the center. Toss the cauliflower florets with 1 tablespoon olive oil, salt, and pepper. Spread them evenly on a rimmed baking sheet and roast for 15 minutes. Turn the florets over and continue roasting for about 25 more minutes until tender. Remove from oven, cool slightly, then thinly slice. Drizzle with truffle oil and toss gently to coat. Reduce oven temperature to 350°F (175°C) for later use.
- Prepare Pie Crust: Press the refrigerated pie crust into a 9-inch tart pan with a removable bottom, covering the bottom and sides. Line the crust with foil and fill with pie weights to prevent bubbling. Bake for 20 minutes, then remove the foil and weights and bake for an additional 5 minutes until the crust turns golden. If bubbles form, gently press them down with the back of a fork. Let the crust cool completely while maintaining the oven temperature.
- Caramelize Onions: Heat the remaining 1 1/2 tablespoons olive oil in a heavy large skillet over medium heat. Add the sliced onions and sprinkle with salt and pepper. Cook, stirring occasionally, for about 40 minutes until the onions become deep golden brown and caramelized. Remove from heat and let cool slightly. (Note: Onion and crust can be prepared a day ahead; store crust at room temperature and refrigerate onions and cauliflower separately.)
- Assemble the Tart: Brush the inside of the cooled crust (bottom and sides) with Dijon mustard. Spread the caramelized onions evenly across the crust. Arrange the sliced roasted cauliflower over the onions in an even layer. Place the tart pan on a rimmed baking sheet for easy handling.
- Prepare Filling and Bake: In a medium bowl, whisk together eggs, mascarpone cheese, whipping cream, ground white pepper, and nutmeg until smooth. Stir in the grated Gruyère cheese. Pour this mixture over the vegetables in the tart crust. Sprinkle grated Parmesan cheese evenly on top. Bake at 350°F for about 40 minutes, or until the tart is golden and the center is set. Remove from oven and transfer to a wire rack to cool for 15 minutes before serving.
Notes
- The tart can be prepared a day in advance—caramelize onions and roast cauliflower ahead, store separately in the refrigerator, and keep the baked crust at room temperature.
- Using truffle oil adds a luxurious, earthy aroma to the roasted cauliflower.
- Ensure onions are cooked slowly to achieve deep caramelization without burning.
- Gruyère cheese provides a creamy, nutty flavor, while Parmesan adds a sharp finish on top.
- The tart is delicious served warm or at room temperature, perfect for entertaining or a cozy meal.
- Prep Time: 25 minutes
- Cook Time: 1 hour 20 minutes
- Category: Tart
- Method: Baking
- Cuisine: French
Keywords: cauliflower tart, caramelized onion tart, vegetarian tart, savory tart, roasted cauliflower, mascarpone tart, Gruyère cheese tart
