Measure and prepare all the ingredients for the recipe.
In a large bowl, mix together the milk, egg, salt, pepper, and breadcrumbs. Let the breadcrumbs soak up the liquids.
Add and mix in the garlic, onion, celery, carrot, parsley, oregano, and ground beef. Mix well.

In a separate bowl, combine the mozzarella cheese, sun-dried tomatoes, and basil.
On a sheet of wax paper, spread the meat mixture into a rectangle.
Place the mozzarella filling in the center.

Using the long side of the wax paper, roll up the meat, peeling away the paper as you go.
Grease a baking sheet and place the meat roll on it.

Preheat the oven to 400°F (204°C).
Roast the meatloaf in the oven for 45 minutes. If your oven has a broiler, turn it on and brown the top of the meatloaf for about 10 minutes.
Remove from the oven and let it rest for about 5 minutes.
Slice and serve with Cremini mushroom sauce.