Spread the pastry in a tray and put the dijon mustad on it. Spread it all over to make a thin layer. Put it in the oven for 5 mins.
Cook the spinach in a pan for a 10 mins with a bit of water to not stick. Let them reduce completely.
Chop the goat cheese into small pieces smaller around 1 cm or smaller.
Place the goat cheese and the spinach on the pastry to be disposed evenly all over the area, and cover a bit of the whole plate.
Wisk the eggs in a bowl, add some salt, pepper and the creme fraiche. Mix it all together, and pour on top of the rest to cover it all. Finally spread the grated cheese on top.