Prep the carrots. Slice the carrots into even rings for consistent cooking. Bring a pot of salted water to a boil and cook the carrots for about 9 minutes — you want tender-crisp, not mushy.
Add the onions. Slice the onions into rings and add them to the pot for the final 6 minutes of cooking. Drain well once done.
Build the base. Dice your green chilies or green pepper (chilies for heat, pepper for a milder, sweeter crunch). Combine the carrots, onions, and chilies/peppers in a glass or ceramic bowl — avoid stainless steel, as the acidic dressing will react with the metal. A large glass jar works beautifully here too.
Make the sauce. In a saucepan, whisk together the water, tomato cream soup powder, vinegar, sugar, oil, Worcestershire sauce, and mustard. Bring to a boil and simmer for about 5 minutes, stirring occasionally.
Combine and chill. Pour the hot sauce directly over the vegetables while it's still warm — this helps the flavors soak in properly. Cover and refrigerate for at least 24 hours. The salad only gets better after 2–3 days, so don't be afraid to make it well ahead of time.
Serve. Spoon into a jar or serving bowl straight from the fridge. Perfect alongside roast meats, on a holiday buffet, or as a tangy addition to a braai spread.