Mix together the onion, garlic, tomatoes, parsley, thyme, bay leaf, mustard, Worcestershire sauce, and salt and pepper to taste.
Spread the mixture on the steak.
Roll the steak up with the grain and tie securely with string.
Place in a flameproof casserole, cover, and refrigerate until the following day.
Cover with equal quantities of beef stock or water, and dark beer.
Bring to a boil, reduce the heat to a bare simmer, and cook, partially covered, until the steak is tender and the liquid reduced, about 2 hours.
Remove the steak from the casserole, brush it with the butter, and roll it in the breadcrumbs.
Arrange the steak in a baking tin and bake in a preheated hot (400 F) oven until the crumbs are lightly browned, about 15 minutes.
Heat the sauce remaining in the casserole and serve in a sauceboat.
Slice the steak and arrange on a warmed platter.
Serve with papas chorreadas.