Clean the sprouts, halve the larger heads, cover with salted water and bring to the boil. Turn the temperature down to a medium heat and cook the sprouts for about 10 minutes until not too soft. Dust the puff pastry lightly with flour, grease the tart dish (22 cm diameter) and line it with the pastry. Shape an edge and remove the excess pastry. Spread the sprouts on the puff pastry. Break open the eggs, add milk, whisk and season with pepper, salt and nutmeg. Mix the Emmental into the eggy milk and pour it evenly over the sprouts. Sprinkle bacon along with the sunflower seeds over the cheese. Bake the quiche in a preheated oven on the middle shelf at 200° for about 25 minutes until the cheese begins to brown. Cover the quiche and slide the grate on the bottom shelf in the oven. Bake the quiche for a further 10 minutes with bottom heat.