Crust – 260 g 1 3/4 cups + 2 TBSP or 9.2 oz all-purpose flour – 140 g 1 1/5 sticks or 4.9 oz unsalted butter, frozen – 4-8 tablespoons ice cold water Filling – 1 tablespoon olive oil – 1 teaspoon salt – 2 large leeks about 550-600g / 1.2 pounds both – 350 g 12.3 oz brussels sprout – 1/4 teaspoon dried thyme – 1 tablespoon butter – 2 eggs beaten – 120 ml 1/2 cup milk – 120 ml 1/2 cup whipping cream – 1/2 teaspoon salt – few grinds of black pepper – 1/8 teaspoon ground nutmeg – 50 g 1.8 oz Parmesan cheese (or similar) – 1-2 tablespoons pumpkin seed – 1 tablespoon olive oil – For serving: Sour cream or créme fraiche or greek yogurt