Brussel Sprout, Leek and Gruyere Tart

• 1 14-oz. sheet puff pastry, defrosted in the refrigerator overnight
• 2 tbsp (30 ml). extra-virgin olive oil
• 1 leek, white and light green parts, sliced thin
• 10 oz (280 grm). Brussels sprouts, halved
• Salt
• Ground black pepper
• 2 tbsp (30 ml). balsamic vinegar
• 1 tbsp (15 ml). finely chopped fresh thyme leaves
• 4 oz (112 grm). shredded Gruy re cheese 1 egg, lightly beaten

1. Line a baking sheet with parchment paper.
2. Unfold the puff pastry and place in middle of baking sheet.
3. Prick all over with a fork.
4. Cover with plastic and place in freezer.
5. Preheat oven to 425 degrees (225 C.).
6. Heat olive oil in a large nonstick skillet over medium-high heat.
7. Add leek and cook until softened, about 3 minutes.
8. Add Brussels sprouts, salt and pepper to taste and cook, stirring occasionally, until they are spotty brown, 5 to 7 minutes.
9. Add balsamic vinegar and continue to cook, stirring, until most of the liquid has cooked off (this will take less than 30 seconds).
10. Scrape into a bowl, stir in thyme and set aside to cool.
11. Remove puff pastry from freezer, and spread cooled Brussel sprouts mixture over it, leaving a 1-inch border all around.
12. Sprinkle the cheese over the Brussels sprouts.
13. Brush edge of dough with egg.
14. Bake until the pastry is golden and cheese is browned and bubbling, about 20 minutes.
15. Cool slightly and serve warm or let come to room temperature before serving.

pastry, extravirgin olive oil, thin, brussels sprouts, salt, ground black pepper, balsamic vinegar, thyme, egg

Taken from online-cookbook.com/goto/cook/rpage/001C77 (may not work)