Cauliflower & Caramelized Onion Tart

Total Time: 3 hrs 10 mins Preparation Time: 30 mins Cook Time: 2 hrs 40 mins

Ingredients

• Servings: 8
• 1 small head cauliflower, cored, cut into 1-inch florets (about 1 pound)
• 2 1/2 tablespoons olive oil, divided
• 1 tablespoon truffle oil
• 1 refrigerated pie crust
• 2 large onions, halved lengthwise, thinly sliced
• 1 tablespoon dijon mustard
• 2 large eggs
• 8 ounces mascarpone cheese
• 1/2 cup whipping cream
• 1/4 teaspoon pepper
• 1 pinch ground nutmeg
• 1 cup grated gruyere cheese
• 3/4 cup grated parmesan cheese

Recipe

• 1 position rack in center of oven; preheat to 425°f
• 2 toss cauliflower with 1 tablespoon olive oil in large bowl.
• 3 spread on large rimmed baking sheet, spacing apart.
• 4 sprinkle with salt and pepper.
• 5 roast 15 minutes; turn florets over.
• 6 continue roasting until tender, about 25 minutes longer.
• 7 cool cauliflower, then thinly slice.
• 8 drizzle with truffle oil; toss.
• 9 reduce oven temperature to 350°f.
• 10 press pie crust onto bottom and up sides of 9-inch-diameter tart pan with removable bottom.
• 11 line pie crust with foil; fill with pie weights.
• 12 bake crust 20 minutes.
• 13 remove foil and pie weights; bake until crust is golden, about 5 minutes, pressing crust with back of fork if bubbles form.
• 14 cool crust.
• 15 maintain oven temperature.
• 16 heat remaining 1 1/2 tablespoons olive oil in heavy large skillet over medium heat.
• 17 add onion; sprinkle with salt and pepper.
• 18 cook until onion is deep golden brown, stirring occasionally, about 40 minutes.
• 19 cool slightly.
• 20 do ahead can be made 1 day ahead.
• 21 store crust at room temperature.
• 22 cover and chill cauliflower and onion separately.
• 23 brush bottom and sides of crust with mustard.
• 24 spread onion in crust.
• 25 arrange cauliflower evenly over.
• 26 set tart on rimmed baking sheet.
• 27 whisk eggs and next 4 ingredients in medium bowl.
• 28 stir in gruyere.
• 29 pour mixture over filling in tart pan; sprinkle with parmesan.
• 30 bake until tart is golden and center is set, about 40 minutes.
• 31 transfer to rack; cool 15 minutes before serving.