Tomato and Goat Cheese Tart

Bahan-bahan (9 porsi)

• all-purpose flour, (for rolling)
• 1 sheet frozen puff pastry, (thawed)
• 1½ tablespoons sour cream ((light is fine))
• 1½ teaspoons grainy Dijon mustard
• sea salt
• freshly ground black pepper
• 2 large leeks, (white and green parts only)
• 1 tablespoon butter
• ¾ pound small beefsteak tomatoes, (sliced ¼ inch thick)
• 2 ounces goat or feta cheese
• 8 to 10 small basil leaves