CAULIFLOWER AND CARAMELIZED ONION TART
Makes 8-12 servings
1 small head cauliflower (about 1 lb.), cut into 1-inch florets
1 tablespoon olive oil
1 tablespoon truffle oil
1 single recipe pie dough (for 9-inch tart pan)
1 1/2 tablespoons olive oil
1 large onion, halved lengthwise, thinly sliced
1 tablespoon Dijon mustard
2 large eggs
1 (7- to 8-ounce) container mascarpone cheese (Italian cream 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
1. Position rack in center of oven; preheat to 425° F.
2. Toss cauliflower with 1 tablespoon olive oil in large bowl. Spread on large rimmed baking sheet, spacing apart. Sprinkle with salt and pepper. Roast 15 minutes; turn florets over. Continue roasting until tender, about 25 minutes longer.
3. Reduce oven temperature to 350° F.
4. Cool cauliflower, then thinly slice. Drizzle with truffle oil and toss.
5. Heat olive oil in heavy 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.
6. Roll pie dough and press onto bottom and up sides of 9-inch tart pan with removable bottom. Line crust with foil; fill with pie weights. Bake for 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.
DO AHEAD: Cauliflower, onion and crust can be made 1 day ahead. Store crust at room temperature. Cover and chill cauliflower and onion separately.
7. Whisk eggs, mascarpone, cream, white pepper and nutmeg in medium bowl. Stir in gruyère.
8. Brush bottom and sides of crust with mustard. Spread onion in crust. Arrange cauliflower evenly over. Set tart on rimmed baking sheet. Pour mixture over filling in tart pan; sprinkle with parmesan.
9. Bake until tart is golden and center is set, about 40 minutes. Transfer to rack; cool 15 minutes before serving.