Rinse the spinach and cut off the tough stalks. Wash the potatoes, peel and cut into a small dice.
Pour 3 tablespoons of olive oil into a large and wide pot with a thick bottom or large pan and over very low heat soften the finely diced onion. Add potatoes and fry for about 1-2 minutes. Add spinach and fry while stirring for about 1 minute over low heat until it wilts slightly.
Pour in white wine and evaporate for a moment. Add water, a pinch of salt, sugar and bring to a boil over medium heat. Reduce heat to minimum and cook for about 15 minutes (the soup should only simmer, it cannot boil hard!).
Blend the soup or press through a strainer, not necessarily into a perfectly smooth puree, leaving very small pieces of spinach and potatoes. Season with salt and pepper.
Heat the soup and serve with shrimp (recipe below), with mascarpone cheese and baguette.
Thaw frozen shrimp in the refrigerator, rinse and dry. Make an incision along the outside of the back starting from the thicker part (this way during frying the sides of the shrimp will spread open).
Heat olive oil in a pan and over low heat soften the finely diced onion. Add shrimp and fry over low heat for 1 minute on each side. Season with salt and pepper. At the end add the parsley, stir.