I believe in experiments, always diving-in and trying something I can’t quite fathom. Almost every time, I am delightfully surprised, as I was with this delicious Tuna and Sweet Onion Tart. I remained true to the concept, tweaking the ingredients a bit and adding a few of my own touches. Michael loves ranch dressing, and since I had a jar of Lighthouse Brand Homestyle Ranch Dressing in the frig, I made a Romaine wedge-type salad, adding chopped Kiolbasa Brand bacon, fried crisp, and peeled, seeded, strips of tomato.

I believe that wining and dining always go hand in hand, so in the spirit of the French-inspired tart, I poured a lovely and light Provencal Rose. All you need to do is add candlelight, beautiful music, a warm fall evening, and dine al fresco for a truly special dinner.

Tuna and Sweet Onion Tart

Serves 4-6

Inspired by a recipe from Laura Calder’s cookbook Paris Express, this tart is simple to make, lovely enough for a romantic dinner for two, and appropriate for a picnic; a bonus is that it can be made hours ahead of serving.

A note about cooking by weight, not measurements. I discovered – only recently – what a difference cooking by weighing ingredients makes vs using measuring cups. If you have a kitchen scale, use it!

Whole Wheat Tart Shell

• 88 grams whole-wheat flour (approximately 3/4 cup)
• 88 grams all-purpose flour (approximately 3/4 cup)
• 1 1/2 teaspoons Diamond Crystal kosher salt

• 8 tablespoons (1 stick) unsalted butter cut in 1/2″ cubes

• 3 tablespoons cold water

• Pam non-stick spray for spraying the tart pan

Tart Filling

• 2 very large Vidalia, Walla Walla, Texas 1015 or Maui onions, sliced lengthwise into thin strips, separated
• 2 tablespoons olive or canola oil
• 1 teaspoon Diamond Crystal kosher salt

• Two 6.7-ounce jars of good quality oil-packed tuna, drained and flaked (Spanish or Italian if available)
• 3/4 cup tomato puree

• 2 eggs
• 1/4 cup crème fraiche
• Diamond Crystal kosher salt to taste
• Freshly ground black pepper to taste
• 1/8 – 1/4 teaspoon Piment d’Espelette or to taste

• 1 cup grated comté cheese (optional)

Special Equipment

• 9 3/4″ or 10 1/4″ x 1″ round tart pan with removable bottom

• Parchment paper

• Pie Weights (I prefer the metal beaded chain type—no runaway pieces, easy to remove and store)

• Kitchen scale that weighs grams, ounces, and pounds

For the tart shell:

Place whole wheat flour, white flour, and salt in the food processor, pulsing lightly to blend. Add butter and pulse until the mixture looks like a coarse meal. Drizzle cold water through the feed tube, pulsing intermittently as you add the water until the dough begins to gather into larger clumps. DO NOT OVERMIX! Place the dough on a lightly floured silicone pastry mat or pastry cloth, and form into a flat round. Wrap with plastic wrap and refrigerate for 1—2 hours.

Spray your tart pan with Pam. Roll out dough (it will be very firm—be patient) and line the tart pan. Use a fork to pierce rows of holes in the bottom, about an inch apart. Note: You may have to piece the pie dough to fill in the edges—don’t worry, it works; just press firmly to attach to the main piece of dough. Can be prepared a day ahead. Refrigerate uncovered.

Heat oven to 325°F. Unwrap the tart shell, place it on a half-sheet pan or baking sheet, and line the dough with a parchment. Fill to the top with pie weights. (Note: you can use rice or dried beans, but my preference is pie weights.) Place the tart shell on the middle rack of the oven for 15 minutes. Remove the pie weights and parchment paper and return the pastry to the oven. Bake for 15 to 20 minutes more, or until lightly browned. Remove from the oven, place on a cooling rack, and allow to become completely cool before filling.

While the tart shell cools, prepare the filling:

Increase the oven temperature to 400°F.  Heat oil in a large skillet and add onions. Sprinkle onions with 1 teaspoon of salt and sauté onions in oil over medium heat until soft and golden but not caramelized. Note: The use of the recommended onions adds a delightful hint of sweetness to the tart. If this doesn’t appeal to you, use large yellow onions in their place.

Remove 3/4 – 1 cup of onions and set aside—optional.

Stir the drained, flaked tuna into the onion mixture, and add the tomato puree. Cook until thick—this can take 30 seconds to 10 minutes. Remove from the heat.

Combine the eggs, crème fraiche, salt, pepper, and Piment d’ Espelette with the tuna mixture. Taste for additional seasoning. Pour the mixture into the tart shell and bake until the filling is hot, firm to the touch, and the pastry is crisp. Approximately 30 minutes. Set on a cooling rack and allow to come to room temperature before serving. 

Serve as is, or if you want to be a bit fancy for a special dinner, mound the reserved sauteed onions in the center and surround with a wreath of shredded comté cheese. Place well below the broiler (at least 12-inches), and broil for a minute or two (watching carefully) until the cheese has just melted.  Do not allow to brown. Note: A slice of this tart is also delicious the next day, straight from the refrigerator, for lunch. Add a glass of wine and a small green salad, and you have a delightful alfresco lunch.