Onion Tart with Soubise and Chives

Ease of Preparation: Medium
Yield: Serves 4, as a main
Onion Tart with Soubise and Chives
This savoury tart highlights many members of the allium family. The rich, buttery leek soubise pairs perfectly with the sweet, caramelized onions to create a filling, well, filling. The fresh, oniony burst of chives rounds out the finish.
Ingredients:
Caramelized Onions:
- ¼ cup (60 ml) vegetable oil
- ¼ cup (60 ml) butter
- 10 medium onions, peeled and sliced into medium thick slices
- Salt and pepper
- ¼ cup (60 ml) sweet molasses
Leek Soubise:
- 5 tablespoons (75 ml) butter
- 6 leeks, white and light green parts only, washed and thinly sliced
- 1 ½ cups (350 ml) heavy cream
- Salt and white pepper
- 3 tablespoons (45 ml) Champagne vinegar
To Assemble:
- Leek Soubise
- Caramelized Onions
- 1 prepared pie dough, divided into 4 pieces
- Flour, for rolling dough
- 1 bunch chives, thinly sliced
Special Equipment:
- 4x 4-inch (10 cm) tart pans with removable bottoms
- Parchment paper and pie weights (such as dried beans)
Method:
For the Caramelized Onions:
In a large, wide pan or rondeau, heat the oil and butter until foamy. Add the onions and a large pinch of salt.
Sweat the onions over low heat until softened and lightly browned, about 40 minutes.
Season well with salt and pepper.
Turn the heat off under the pan, add the molasses to the onions, and stir well to coat each piece. If the onions seem wet or goopy, turn the heat back to low and cook, stirring often, until shiny and sticky.
For the Leek Soubise:
In a medium saucepan, melt the butter. When foamy, add the sliced leeks and sweat until very soft and translucent, about 8-10 minutes.
Add the cream and bring the mixture to a simmer. Cook until the cream is thickened and reduced, another 2 minutes.
Transfer the mixture to a high-powered blender. Blitz until smooth and silky.
Add the Champagne vinegar.
Pass the purée through a fine-mesh strainer, season well with salt and white pepper and set aside to keep warm.
To Assemble the Tart:
Preheat the oven to 350 F (175 C). Grease the 4 tart pans.
Flour a clean work surface and roll out the pie dough pieces into 4 rounds. Transfer to the prepared pans.
Lay parchment paper over the dough and fill with pie weights (such as dried beans).
Bake for 15 minutes, then remove the parchment and weights.
Bake uncovered for 3 minutes, until the crust is cooked through and firm.
Using a spatula, divide the Leek Soubise into the tart shells, ensuring it’s evenly distributed and flattened out. Cover neatly with the Caramelized Onions.
Garnish with chives and serve immediately.