Caramelized onion tart with black olives
Elegant French savory tart topped with caramelized onions, black olives, and optional anchovies.
Ingredients
Caramelized onions
- 5 onions yellow, brown, or white (not red)
- 1 tbsp olive oil (extra virgin)
- 1 tbsp butter (unsalted)
- 3/4 tsp kosher salt can omit for lower-sodium version
- 2 sprigs thyme (fresh)
Caramelized onion tart
- 1 sheet puff pastry (gluten-free) Schar brand, thawed overnight in the fridge
- 1 tbsp Dijon mustard or mayonnaise
- 1 cup caramelized onions recipe here
- 1/3 cup olives (black) I used 4 olives total, thinly sliced, to reduce the sodium
- 8-10 anchovy fillets oil-packed, can omit
Instructions
Caramelized onions
- Cut the onions in half from stem to root end, peel, and thinly slice. Don’t be perfect about it. Discard any tough root ends. Alternatively (saving time and tears), you can use the slicing disc on your food processor to slice peeled, quartered onions.
- Heat a large heavy-bottomed pan (with an available lid) over medium-high heat. Add the olive oil and butter.
- Once the butter is melted, add the onions. Stir. Add the salt and thyme. Keep stirring every few minutes. The onions will give off about a cup of liquid almost immediately.
- When the onions have softened a bit and are starting to turn translucent (about 5 minutes), turn down the heat to low and throw on the lid. Cook, covered, stirring every 10 minutes or so, until the onions have turned very soft, translucent, and very sweet, and have released a good cup or two of juices, at least one hour and up to two.
- If the onions start to brown, add a splash of water or chicken stock.Remove the lid for good, turn the heat to medium-high, and bring to a gentle boil. Cook, stirring almost constantly, until nearly all the liquid in the pan has evaporated and the onions have taken on a marmalade-like consistency (golden yellow, honey-sweet, and still moist), about 15 minutes.Stay with it. Don’t let it burn. Stir, stir, stir.
- Locate the thyme sprigs and discard. Taste. Add salt if needed. Cool. The onions keep in a covered container for a few days in the fridge and for several months in the freezer.
Caramelized onion tart
- Take your tart dough out of the fridge or freezer. Once it’s soft enough to roll out, preheat the oven to 350ºF.
- Roll out your tart dough until it’s about 10 inches in diameter and ⅛-inch thick. Press into an 8-or 9-inch tart pan. You can also do this as a free- form tart. [The Schar gluten-free pastry comes on a piece of parchment paper and is already 1/8" thick so just unroll it and put it on a baking pan, covering the entire crust in the next step.]
- Thinly spread the mustard or mayonnaise over the puff pastry with a pastry brush or a butter knife. Spread a cup of the caramelized onions over the crust. Top with olives and anchovies (if using) in any pattern that you like.
- Bake until the crust is just set and the onions are golden brown, about 35 to 40 minutes. [You should be able to lift it up with a spatula and it's like a board, not sagging in the middle.]
- Serve warm or at room temperature with a crisp green salad. Freezes beautifully.
Notes
Recipe courtesy of Phyllis Grant. Used with permission.