Boil the eggs in a pot of salted water until soft-boiled (about 8 minutes), then remove shells and slice.
To prepare the stuffing for the roast, sauté the sausage and 1/2 of the onion in a small amount of oil over medium heat until browned (about 10 minutes).
Lay out the flattened flank steak and spread the sausage mixture over the center.
Next layer the bacon, boiled eggs, cheese and garlic over the meat.
Roll up the flank steak, tie with kitchen twine, and season with salt and pepper.
Add a small amount of oil and the rest of the onion to a large pot. Place the meat into the pot and brown, over medium-high heat, on all sides.
Deglazed the pot with the red wine and cook until mostly evaporated.
Add the tomato sauce and beef stock, lower the heat and let the roast simmer, covered, until cooked through (about 1 hour), occasionally spooning the sauce over the roast to keep moist.
Remove the roast from the pot and cover in foil to let rest (about 15 minutes).
Cut off the string and cut the meat into 1" thick slices to serve.