Leek & Goat Cheese Tart

• 10 tart shell
• 6 leeks
• 1 pre (baked)
• 1/4 rounds
• 200 gr goat cheese
• 120 ml cream (heavy)
• 30 ml balsamic vinegar
• 28 gr butter
• 1 gr salt
• 1 gr pepper (freshly ground)