In a deep and wide bowl, mix the egg with the milk, the mustard and the ketchup. Beat well and add the two slices of chopped bread. Mash with a fork until obtain a homogeneous porridge in which no pieces of bread are noticeable. Add the Provencal herbs, the garlic salt and season to taste.
Add the minced meat and mix with your hands (very clean) so that all the ingredients and flavors are integrated. Let the mixture rest for an hour in the fridge., with the container well covered. Meanwhile, we prepare a homemade tomato sauce. Do not buy it prepared, this is a very important point to make our meatballs go from being delicious to simply being “the definitive meatballs”.
When the meat mixture has rested, we form the meatballs. We take small portions, ball them and pass them through flour. It will take a little longer if we make them small, but the result is more delicate and then they will cook faster in the sauce. Is It is a soft dough, but it can be handled and results in meatballs that are tender inside and very juicy.
Once the meatballs are coated, heat plenty of extra virgin olive oil in a frying pan and fry them over high heat for a minute. We want to are sealed on the outside, so we turn them carefully when frying. Drain the meatballs on absorbent paper before transferring them to a saucepan with the tomato sauce and cook for 10 minutes. We serve immediately.