Peel the potato and wash thoroughly. Then with a slicer or a sharp knife, cut the potato into very thin round slices.
Cut the tomatoes length wise into thin long slices and discard the seeds. Finely slice the onion lengthwise.
The sausages need to be in room temperature and cut them into small size. Roughly tear the basil with your hands and keep aside.
In case you are baking, then use a baking dish or a skillet or a frying pan which goes into the oven. It should be approximately 9 inches in diameter. In case you are doing on stove top, then the process below has to be done in a frying pan.
Spread olive oil nicely at the bottom and the sides of the pan. Then arrange the potato slices at the bottom of the dish, covering the entire bottom.
Top that with onion slices and then a layer of tomatoes. Then cover this with the roughly chopped spinach leaves. Top it with sausages sprinkled all around.
In a mixing bowl, break the eggs, add milk, basil leaves, salt and pepper. Whisk thoroughly till frothy. Fold in the grated cheese to the eggs.
Then pour in the eggs over the vegetables.
Transfer the baking dish in the oven and cook for 10 minutes at 180 degrees. Take it out of the oven when the egg has set. In the stovestop, you will have to cover and cook on a low flame till the egg has cooked.
Slice it into pizza cones and serve with a crusty bread on the side.