Place the peeled potatoes in a pan, cover with water and bring to the boil to cook until soft.
Mix all the ingredients except the breadcrumbs.
After mixing the ingredients well and obtaining a homogeneous mass, gradually add the breadcrumbs as needed.
The amount varies depending on the moisture of the meat and other factors.
Add just enough to get a moldable mixture.
Divide the mixture into 7 or 8 parts, form a ball and flatten slightly.
With your thumb, press the center to make a cavity that will then receive the puree.
Place the meatballs in the fridge while you prepare the rest.
Discard the cooking water and mash the potatoes well.
Add the butter and cream and mix well.
The idea of this step is to obtain a puree with creaminess, but slightly firm.
If necessary add a little more cream.
Season with salt and nutmeg and set aside to cool slightly.
Reserve to cool.
Heat a frying pan, add oil, onions and sauté.
Mash the peeled tomatoes and place in the frying pan, add salt and let it boil to thicken the sauce, add a little water if necessary.
Season with pepper and set aside.
Take the meatballs from the fridge, with a spoon or using a pastry bag/tube, generously fill the cavity with the puree.
Place the tomato sauce on the bottom of a platter, place the meatballs and bake in a heated oven at 200C for approximately 30 minutes.
To make my puree look beautiful, I used this tube with a Pitanga pastry nozzle, I found it in a supermarket here in Porto Alegre, it is practical to wash and easier to use than a pastry bag.
Remembering that you can accommodate the puree with a spoon, be sure to make this delicious recipe.