For the onions:
Heat oil in a skillet over medium, add onions, salt & pepper, cook 15-20 minutes, stirring frequently or until caramelized.
Add thyme, sauté for minute or two, then add the wine and beef broth.
Reduce until very little liquid remains.
Set aside.
For the meatloaf:
Preheat oven to 350°F.
In a bowl, combine ground beef, bread crumbs or oats, parsley, pepper, salt, and eggs. Gently combine with your hands until blended, but try not to overwork the meat.
On a piece of plastic wrap or wax paper, press the meat mixture into a 10×12-inch rectangle.
Set aside ½ cup shredded mozzarella cheese and ½ cup og the caramelized onions. Sprinkle the remaining 1½ cups cheese and the caramelized onions evenly over ground beef. Roll up like a jelly roll, starting from the short end, lifting the wax paper or plastic wrap as you roll. Seal the end completely, and place seam-side down into a 9×13-inch baking pan.
Sauce – whisk together, bring to boil, simmer till thickened.
Place pan in the oven and bake for 45 minutes. While the meatloaf is baking, prepare the sauce (see below).
Remove pan from oven, pour the sauce over the meatloaf, and sprinkle with the reserved onions and cheese.
Return meatloaf to oven 15-20 minutes, or until no pink remains. Place under the broiler for 2-3 minutes, or until the cheese is browned and bubbly.
Garnish with fresh parsley, if desired. Remove from oven and allow to stand 10 minutes. Slice and serve.
For the sauce:
Whisk ingredients together in a small saucepan, and bring to a boil over medium heat.
Reduce to a simmer until reduced and thickened.
