Place cauliflower in a medium shallow pot or pan. Add stock, cover and place pot over high heat. When liquid boils, reduce heat to simmer and cook covered 10 minutes. Remove cover, raise heat to medium high and allow the broth to reduce by half, 2 minutes. Add 2 tablespoons butter, cut into pieces and the cheeses and smash the cauliflower with a masher to the same consistency as desired for mashed potatoes. Season the cauliflower with black pepper, a pinch of salt and nutmeg.
Turn broiler on. Brush meat with Worcestershire and season with salt and pepper. Cook London broil on top rack for 6 minutes on each side, for medium rare to medium doneness.
While steak and cauliflower cook, heat a second large skillet over medium-high heat. Add oil, 2 turns of the pan, and ham. Sear ham and caramelize at edges, 2 minutes.
Add chard and wilt the greens into the pan then season with salt, pepper and a dash of nutmeg, optional. Cook 5 to 7 minutes more, turning frequently with tongs then add vinegar to the pan and a drizzle of honey. Turn to coat the greens, adjust seasoning and transfer to a serving dish.
Remove meat from broiler and let it rest 5 minutes.
Place a small skillet over medium heat. Melt remaining 2 tablespoons butter, add finely chopped shallot, cook 2 minutes, then whisk in flour and cook 1 minute. Add 2 cups beef broth to the pan and bring to a bubble. Reduce the broth 2 minutes then add 1/4 cup steak sauce and black pepper, to taste.
Very thinly slice the meat on an angle against the grain (the lines in the meat). The degree to which you can slice thinly slice the meat will determine how tender it is to cut and chew, so make sure the carving knife is sharp ¿ the thinner the better!
Serve sliced London broil with steak sauce gravy all over it and smashed cauliflower and red chard with ham piled up alongside the meat.