Roll puff pastry, on lightly floured surface, into two 10-inch (25 cm) squares. Cut each square into 4 portions; arrange on 2 parchment-lined baking sheets. Score a 1/4-inch (5 mm) border around each portion. Place in freezer for 20 minutes.
Meanwhile, place bacon in preheated non-stick skillet set over medium-high heat. Cook for 10 minutes or until starting to brown. Add mushrooms, thyme and garlic. Cook for 10 minutes or until mushrooms are browned and tender. Stir in tomatoes and remove from heat; cool slightly. Stir in cheese.
Preheat oven to 400°F (200°C). Remove puff pastry from freezer. Beat 1 egg with 1 tsp (5 mL) water. Brush around border of each portion of puff pastry. Spoon tomato mixture over pastry, staying within border.
Bake for 15 minutes or until lightly browned. Remove from oven and crack an egg into centre of each tart. Sprinkle with salt and pepper. Bake for 8 to 10 minutes or until white is set and yolk is still slightly runny.
Add 1 tbsp (15 mL) oil and omit the bacon to make this a delicious vegetarian dish.