Red Onion Tart
This savoury red onion balsamic, and thyme pastry is a great option for a light lunch or enjoy it with a side salad for dinner.
For this tart recipe, you will need a tart pan, or tart dish. This one pictured below is a long (13.6" x 5.1") rectangular tart dish with deep sides that stands up well (see details below). If you don't have this tart dish, then I have selected a few other options below under equipment. As long as it is a rectangular tart pan, it will work well. View the quick video to help and inspire you to make this tart.
Pairings:
Serve this red onion tart with fresh leafy greens, or rocket salad (arugula) with a vingeriette. If you love onions, this tart is for you, and if you love other types of onion tarts, then you will enjoy my blue cheese onion tart, get it here in my FREE autumn e-book, with other recipes like my Chicken Tagine with Preserved Limes, and Ginger Sage Harvest Cider cocktail (with a mocktail alternative).
Equipment:
For this tart recipe I used the Emile Henry 13.6" x 5.1" Slim Tart Dish, even though it is slim, it has deep side grooves that are great for pie dough and fills nicely when you use it to its full volume. This is also one of my favourite tart dishes to use for quiches and any tarat that you are using for entertaining. It's also nonstick, so there's no-fuss clean-up!
More Equipment Options
This red onion tart is a delicious savoury and semi-sweet pastry for dinner, or anytime!
Use this savoury pie crust or buy your favourite all-butter pie crusts.
- 2 Savoury pie crusts, *see link in "Prep" step (or shop bought pie crusts)
- 2 large red onions (or 3 medium red onions)
- 2 large cloves garlic, (minced)
- 2 tablespoons olive oil
- 1 teaspoon kosher salt
- 1/2 teaspoon black pepper
- 3 teaspoons honey
- 2 teaspoons chopped fresh thyme leaves, (more to garnish)
- 2 teaspoons Worcestershire sauce
- 4 tablespoons balsamic glaze, (divided in 2 tablespoons)
- 2 large eggs
- 1 teaspoon water
- 1/2 cup (118 ml) unsweetened plant-based milk (whole milk)
- 1/2 cup (120g) fresh Parmesan cheese, (shaved)
- Prep:
- After making the pie crusts, roll out the first pie crust on a lightly floured surface and place it in the tart dish, fitting the dough secure inside and leaving some of the dough overhanging about 1-inch or less (about 2.5cm) on the sides of the tart dish. Crimp the excess dough with your fingers or cut it off. Chill the tart dish and the second pie dough separately in the refrigerator. Proceed to Step 2.
- Fill a medium bowl of ice water. Set aside.
- Slice all of the red onions in half-moon slices. Then, place the onions in the bowl of ice water. Set aside.
- In a small bowl or mug, add 1 egg, and a splash of water, lightly whisk together. Set aside.
- Making the onion filling:
- Preheat the oven to 350°F/180°C.
- Remove the onions from the bowl of ice, and place on a kitchen cloth to remove excess water.
- Heat the olive oil in a large (9 or 10-inch) nonstick skillet, over medium heat, and add the onions, salt, and black pepper. Sauté the onions for 6 minutes, stirring occasionally with a silicone spatular or wooden spoon.
- Now, stir in the honey, thyme leaves, Worcestershire sauce, and 2 tablespoons of balsamic glaze. Cook a further 2 minutes. Switch off the heat and set the skillet of onions aside.
- Remove the tart dish from the refrigerator. Use the prongs of a fork to pierce the dough on the inside bottom of the tart dish, four or five times, piercing the middle and sides. Dip a pastry brush in the prepared egg/water mixture and brush the edges of the pie dough on the tart.
- Place the tart dish in the preheated oven and blind bake for 15 minutes. Remove the tart dish from the oven and set aside.
- Filling the tart dish:
- Add half of the Parmesan cheese over the crust in the tart dish, then evenly spread half of the onion mixture on top of the Parmesan cheese. Layer the tart again, filling it with a little more of the onion mixture, then adding the remaining Parmesan cheese, and onion mixture on top.
- Meanwhile, in a small mixing bowl, add the remaining egg, and milk. Beat together until yolks are smooth. Evenly pour the milk mixture over the tart.
- Bake for 35-40 minutes, or until the edges are golden brown and the top has browned.
- Remove from the oven. Immediately drizzle the remaining 2 tablespoons of balsamic glaze over the tart and garnish with fresh thyme leaves.
- Allow the tart to rest for at least 20 minutes before serving.
*Approximate prep time includes prep steps and making the onion filling.
