Peel the cassava, cut into medium-sized pieces and place in a pot with water.
Bring to the boil and cook gently.
Pass the hot cassava through a sieve.
Add butter, Parmesan cheese and egg.
Knead to a smooth puree. Mix well. The puree should be thick.
Shape into balls.
In the center of each ball 1 slice of mozzarella cheese or butter.
Then do the balls by cassava flour.
In the freezer for a few hours or more rest.
Heat the oil in a frying-pan.
Fry the balls once the oil is hot.
Remove balls from the pan when they are brown.
30 servings
30 ball