Combine ketchup, white sugar, vegetable oil, lemon juice, paprika, chopped onion, minced garlic, Worcestershire sauce, and mayonnaise (if using) in a food processor.

Process the ingredients until the mixture is well blended and smooth.

Add the crumbled blue cheese to the mixture.

Season with salt and black pepper to your preferred taste.

Mix in the blue cheese, salt, and pepper until evenly distributed.

Transfer the dressing to a clean glass jar.

Seal the jar tightly with a lid.

Refrigerate the dressing for at least 6 hours to allow the flavors to meld.