Description
This recipe yields a comforting vegetarian tart featuring slow-cooked sweet caramelized onions, earthy mushrooms, and Gruyère cheese baked on flaky puff pastry.
Ingredients
Scale
- 1 TBSP olive oil
- 1 TBSP butter
- 2 medium yellow and/or red onions, thinly sliced
- 1/2 TBSP brown sugar
- 2 TBSPS Balsamic vinegar
- Sea salt & freshly ground pepper to taste
- 8 oz Cremini mushrooms, cleaned and thinly sliced
- 1 TBSP fresh thyme leaves
- 2 small Yukon Gold potatoes, thinly sliced
- 1 tsp fennel seeds, toasted and crushed (optional)
- 1 sheet frozen puff pastry (half of a 17oz package), defrosted
- 4 oz Gruyère cheese, grated
Instructions
- Heat a large saucepan over medium-high heat. Add the olive oil and butter. Add the sliced onions and cook for about 10 minutes until they wilt and start to brown.
- Add the brown sugar, Balsamic vinegar, salt, and pepper to the onions. Reduce the heat and cook gently, uncovered, for about 20 more minutes until the onions are completely caramelized. Add a little water if the onions dry out. Taste and adjust seasoning. Remove the onions to a separate bowl.
- Add the sliced mushrooms to the same pot and sauté without oil for a few minutes until they release moisture. Add a little olive oil and the thyme leaves and cook, stirring frequently, until the mushrooms lightly brown.
- Add the sliced potatoes and the fennel seeds (if using). Season with salt and pepper and cook for a few more minutes until the potatoes soften slightly. Set the mixture aside to cool.
- Unfold the thawed puff pastry and roll it into a 10”x14” rectangle on a work surface. Move the pastry to a baking sheet lined with parchment paper. Prick the dough every few inches with a fork. Score the perimeter about 1/4- to 1/2-inch from the edge with a sharp knife.
- Spread the cooled onions evenly over the puff pastry. Top with the sautéed mushroom and potato mixture, then sprinkle with the Gruyère cheese.
- Preheat the oven to 375°F. Bake the tart on the middle rack for 25-30 minutes until the cheese is bubbling and the crust is golden brown.
- Allow the tart to cool for 10 minutes before cutting it into 20 small rectangles. Serve warm or at room temperature.
Notes
- This tart tastes good the next day, making it suitable for meal prep or leftovers.
- Serve this tart alongside a simple green salad or a light soup for a complete meal.
- Prep Time: 25 min
- Cook Time: 50 min
- Category: Dinner
- Method: Baking
- Cuisine: General
Nutrition
- Serving Size: 1 rectangle
- Calories: 180
- Sugar: 4
- Sodium: 250
- Fat: 12
- Saturated Fat: 6
- Unsaturated Fat: 6
- Trans Fat: 0
- Carbohydrates: 14
- Fiber: 1
- Protein: 5
- Cholesterol: 20
Keywords: Mushroom Caramelized Onion Tart, savory tart, vegetarian baking, puff pastry recipe, Gruyère cheese, easy baking, comfort food