If sending this lunch warm to school in a thermos container, fill the thermos with hot water for 5 minutes. Empty the hot water out before adding the hot food.
Warm the meatballs and sauce in a microwave-safe dish, covered, for 2 minutes until they’re piping hot.
Assemble:
For a hot lunch: put the meatballs and sauce inside the thermos and close the lid.
At room temperature: put the meatballs in one compartment of the lunch box, skewered or not, and the sauce in another.
Pack the toasted baguette slices, or a bread roll, in a separate compartment or container. Add silverware inside the lunch bag.
Add fruit and any other healthy sides to complete this lunch and put everything inside a lunch bag.