Ingredients

  • j2 medium Yukon gold potatoes, peeled and cut into 1/2-inch-thick rounds
  • 2 medium sweet potatoes, peeled and cut into 1/2-inch-thick rounds
  • 2 medium parsnips, peeled and cut into 1/2-inch-thick rounds
  • 1 small onion, cut into 1/2-inch-thick rounds
  • 4 cloves garlic, halved
  • 3 tablespoons extra-virgin olive oil
  • Kosher salt and freshly ground pepper
  • 3/4 cup sugar
  • 1 tablespoon white wine vinegar
  • 1 tablespoon small fresh sage leaves
  • 1 tablespoon fresh oregano leaves
  • 6 ounces mozzarella, grated (about 1 cup)
  • 1 8 .5-ounce sheet frozen puff pastry, thawed
  • All-purpose flour, for dusting

Method

  • Preheat the oven to 400 degrees F. Toss both kinds of potatoes, the parsnips, onion, garlic, olive oil, 1 teaspoon salt and 1/4teaspoon pepper in a bowl.
  • Spread in a single layer on a baking sheet; bake until tender, about 45 minutes.
  • Let cool slightly.
  • Meanwhile, mix 2 tablespoons water and the sugar in a skillet and bring to a boil over medium heat.
  • Cook, swirling the pan, until amber, about 7 minutes.
  • Remove from the heat and stir in the vinegar and 1/4teaspoon each salt and pepper.
  • Pour the caramel into a 9-by-13-inch glass baking dish and spread with a rubber spatula.
  • Sprinkle the sage and oregano on top.
  • Arrange the roasted potatoes and parsnips in a single snug layer on top of the caramel.
  • Scatter the onion and garlic over the roasted vegetables; sprinkle evenly with the mozzarella.
  • Roll out the puff pastry on a lightly floured surface into a 9-by-13-inch rectangle.
  • Pierce the pastry all over with a fork, then lay it on top of the mozzarella, folding the edges under to fit, if necessary.
  • Bake 20 minutes, then reduce the oven temperature to 350 degrees F and continue baking until the dough is cooked through, 15 to 20 more minutes.
  • Let the tart cool 10 minutes in the baking dish, then carefully invert it onto a cutting board.
  • Replace any vegetables that stick to the dish, if necessary.
  • Photograph by Anna Williams