Season both sides of roast with salt and pepper. Brown meat in large heavy pot or Dutch oven on high heat in 1/4 cup of the Catalina dressing, turning to brown both sides. Add onions; stir to brown.
Add remaining Catalina dressing, potatoes, carrots and enough water to come 3/4 way up meat (about 1 1/2 to 2 cups). Bring to boil; cover. Reduce heat to low. Simmer 2+ hours or until meat and vegetables are tender.
Note:Potatoes can be browned with meat if desired.
Remove meat from pan; slice meat thinly against the grain. Serve meat and vegetables topped with pan gravy. Sprinkle with chopped parsley just before serving.
If thicker pan gravy is desired, stir 1/4 cup water into 2 to 3 Tablespoons flour in small bowl.
Remove meat and vegetables from pan; bring liquid to boil on medium-high heat. Gradually whisk flour mixture into pan liquid until thickened to desired consistency.
The original recipe said to put it in the oven to cook, but I like to make it on the stovetop. I find it cooks better. It's all in one pan and so easy to make. The trick is to make sure you brown both sides of the meat in the Catalina dressing.