In a Large skillet, heat the oil and the salted butter over a Medium heat
When melted, add in the sirloin cubes and season them with seasoning salt, black pepper, white pepper and adobo until the outside is lightly browned but not fully cooked through
Transfer into your crock pot now
Add the beef broth, Worcestershire sauce, mushrooms, brown sugar- then mix in the ketchup - sprinkle the beef with thyme and parsley. Sprinkle the diced onions and garlic over the top.
Cover the slow cooker and cook on Low for 5 hours.
Combine water and cornstarch in a separate small bowl , then pour mixture into the crockpot, then add gravy master & Stir until sauce has thickened - cook on LOW for an additional 15 minutes.
Serve over mashed potatoes
ENJOY!!