Place cubed steak, soy, beer, oil, sugar, shallots, mustard and roasted garlic into an air-tight resealable plastic bag. Combine and ensure all portions of meat are well-covered. Marinate for 8 hours, up to over night. Remove steak from refrigeration 1 hour prior to grilling, discard marinade and rest on the counter until near room temperature.
Meanwhile, preheat the barbecue for direct grilling and medium-high heat.
While the grill is warming to temperature, arrange the marinated beef cubes, mushroom, onion and peppers on the skewers, careful to not overload the ka-bobs. Drizzle with olive oil and season to taste.
Grill the skewers with the grill lid open for 3-4 minutes per side, until the beef has reached an internal temperature of at least 125-130F. Remove skewers from the grill, place under a tin foil tent and rest for 5-10 minutes before serving.
Plate family-style, garnish with parsley and a spoonful of chimichurri per skewer. Serve alongside family, the best of friends and an ice cold craft-brewed amber ale. Cheers!