Sweet and Savory Tomato Tart with Onions

Ingredients

• 250 g All-purpose flour (Sift)
• 125 g Unsalted butter (Soft, diced)
• 1 Egg (Only the yolk used)
• 30 ml Cold water (Add gradually)
• 2 Yellow onions (Peeled and finely sliced)
• 1 tablespoon Olive oil
• 1 tablespoon Maple syrup
• 1 teaspoon Balsamic vinegar
• ½ teaspoon Salt
• ¼ teaspoon Ground black pepper
• 1 teaspoon Dijon mustard
• 30 g Grated Parmesan (For the edges of the crust)
• 4 Heirloom tomatoes (Wash and cut into thick slices)

Instructions

1. Prepare the shortcrust pastry

   Place the flour in the bowl, add the soft butter in pieces and work it in with your fingertips until a sandy texture is achieved. Add the egg yolk, then gradually the cold water until a homogeneous ball forms.

   Time: PT10M

2. Rest the dough

   Flatten the ball slightly, wrap it in plastic film and place it in the refrigerator for 30 minutes.

   Time: PT30M

3. Prepare the onions

   Peel the onions and slice them finely.

   Time: PT5M

4. Sauté the onions

   Heat 1 tablespoon of olive oil in a pan over medium heat. Add the onions, season with salt and pepper and cook, stirring regularly. Add 2 tablespoons of water gradually to prevent the onions from sticking. Cook until they are golden and tender, about 15 minutes.

   Time: PT15M

   Temperature: 180°C

5. Caramelize with maple syrup and vinegar

   Pour the maple syrup and balsamic vinegar into the pan, stir quickly and let reduce for a few minutes until the mixture coats the onions.

   Time: PT2M

6. Prepare the tomatoes

   Wash the heirloom tomatoes, dry them and cut into thick slices of about 5 mm.

   Time: PT5M

7. Roll out the dough

   On a lightly floured surface, roll out the dough into a disc about 30 cm in diameter. Place it on parchment paper.

   Time: PT5M

8. Line the tin and prepare the crust

   Transfer the dough into the 30 cm tart pan, press the edges lightly, trim the excess and fold the edges inward. Sprinkle the edges with grated Parmesan. Prick the base with a fork.

   Time: PT5M

9. Brush with mustard

   Spread Dijon mustard evenly over the tart base using a brush or a spoon.

   Time: PT1M

10. Arrange the toppings

    Spread the caramelized onions in the centre, then arrange the tomato rounds in a rosette pattern. Lightly salt.

    Time: PT5M

11. Bake

    Preheat the oven to 200°C. Bake the tart for 30 minutes, or until the crust is golden and the tomatoes are slightly confit.

    Time: PT30M

    Temperature: 200°C

12. Rest and serve

    Remove the tart from the oven, let it rest for 5 minutes before unmoulding and serving.

    Time: PT5M

Nutrition Facts

Calories

300

Protein

8 g

Carbohydrates

30 g

Fat

15 g

Fiber

3 g

Ingredient Substitutions

• Instead of All-purpose flour: Whole wheat flour
• Instead of Unsalted butter: Margarine
• Instead of Egg: Liquid egg yolk
• Instead of Yellow onions: Shallots
• Instead of Olive oil: Sunflower oil
• Instead of Maple syrup: Honey
• Instead of Balsamic vinegar: Red wine vinegar
• Instead of Dijon mustard: Whole grain mustard
• Instead of Grated Parmesan: Grated Gruyère
• Instead of Heirloom tomatoes: Roma tomatoes

Equipment Needed

• Mixing bowl
• Fork or spatula
• Plastic wrap
• Rolling pin
• Parchment paper
• 30 cm tart pan
• Oven
• Frying pan
• Chef’s knife
• Cutting board
• Tablespoon
• Teaspoon
• Kitchen brush (optional)

Critical Steps — Do Not Skip

• Do not overwork the dough to avoid it becoming tough.
• Let the dough rest in the fridge for 30 minutes.
• Properly caramelize the onions with maple syrup and vinegar.
• Fold the tin edges with Parmesan for a golden crust.
• Bake the tart at 200°C until the crust is well golden.

Chef Tips from the Video

• Lightly sprinkle fresh thyme before baking for an extra aromatic note.
• Use tomatoes of different colors for a more attractive visual result.
• For an even flakier crust, incorporate a small teaspoon of white wine vinegar into the dough.

Troubleshooting

Storage

Refrigerator: Store the tart in an airtight container for 2 to 3 days.

Freezer: Wrap the cooled tart in plastic wrap then aluminium foil, freeze up to 1 month. Thaw in the refrigerator before reheating.

Room temperature: At room temperature, the tart keeps for up to 2 hours.

Make-Ahead Tips

• The dough can be prepared the day before and kept in the refrigerator.
• Caramelized onions keep for 2 days in the refrigerator and can be reheated before assembly.