Spread cornmeal on work surface and roll out pastry ( I like to use an all butter recipe) - incorporating the cornmeal into the pastry. Then press pastry into tart pan and place in refrigerator 30 minutes to rest.
Place onions and garlic in skillet with couple tablespoons of oil and a couple tablespoons of water and salt and pepper to taste. Cook completely until tender and translucent but do not allow to color or brown. Then transfer to separate bowl.
In the same skillet add kale with a couple tablespoons of oil and water and salt and pepper to taste. Cover skillet and allow kale to steam a bit, then uncover cook until tender.
Mix together creme fraiche, cream, eggs, salt and pepper to taste. Set aside.
Bake tart shell for 20 minutes.Remove from ovenand brush with egg. Return to oven for 5 more minutes. Remove from oven and allow to cool slightly
Spread onion mixter evenly over tart crust. Then layer the potatoes over the onions. Evenly spread the kale over the potatoes. Pour the creme fraiche mixer. Then scatter the chourico on top