Mash the boiled cassavas well.
In a pan, put the butter and let it melt, add the onion and the garlic and sauté them, add the salt, gradually add the wheat flour, also add the water gradually, keep stirring and let it all cook for 1 minute, add the cassavas and stir very well for 5 minutes, don't stop stirring.
Transfer to a bowl.
Get a piece of this dough, flatten it and fill it with mozzarella, roll it up into a ball and repeat this process with the rest of the dough.
Coat the balls in a mixture made with 1 ½ cups of wheat flour and ½ cup of water, then coat them in the breadcrumbs. Repeat this process with all the balls.
Fry in very hot oil.