Tomato, Onion and Gruyere Tart
Fresh, juicy and plump tomatoes from the backyard vine top onions caramelized with fresh thyme and umami-rich anchovies (optional), and a layer of nutty and slightly sweet gruyere cheese. And importantly, all easily prepared with frozen prepared puff pastry.
Equipment
- 9.5" tart pan
- 12" skillet
Ingredients
- 1 sheet of prepared frozen puff pastry from a 17.3 oz. package, thawed
- 1 tablespoon Dijon mustard
- 2 large yellow onions thinly sliced
- 2 tablespoons olive oil
- 2 cloves garlic minced
- 1 teaspoon fresh chopped thyme
- 2 anchovy fillets minced optional
- 1 tablespoon balsamic vinegar
- 1-½ pounds heirloom tomatoes
- salt
- 8 ounces Gruyère cheese shredded (about 2 cups)
- Fresh basil for garnish
Instructions
- Preheat oven to 375°F.
- On a lightly floured surface or a piece of parchment, roll out puff pastry to 11” square. Transfer to 9.5” tart pan, pushing pastry up edges and folding overhang toward the center, pressing against side of pan. Pierce the bottom of the crust with a fork several times. Place in the refrigerator for 30 minutes.
- Line the pastry with parchment and fill with pie weights. Or, using foil, form the foil to serve as an insert to retain the pastry shape. (See photo in blog instructions.) Bake for 12 minutes. Remove from oven and remove parchment/pie weights or foil. Bake for 5 more minutes. Once cool, brush the bottom of the pastry with Dijon mustard. Reserve
- Heat oil in a large skillet over medium heat. Add onion, stirring occasionally, until softened and lightly caramelized, about 20 minutes. Add garlic, anchovies (if using), thyme and salt, and stir to combine until fragrant, about one minute. Add balsamic vinegar and cook down completely. Reserve.
- Place sliced tomatoes on a paper towel. Sprinkle with salt. Cover with another paper towel and press down lightly. (This will remove moisture from the tomatoes.) Allow to rest for 15 minutes.
- Spread onion mixture evenly over pastry shell and top with cheese. Arrange tomato slices in concentric circle over cheese. Season with salt and pepper.
- Bake tart in the middle of the oven for 50 minutes, or until pastry is golden. Cool on a rack. Remove rim of tart pan for serving if desired and sprinkle with chopped basil.