Grandmother's Homemade Barbecue Sauce

¾ cup Ketchup
¾ cup Water
1 Medium Red Onion, Diced
2 Tbs Apple Cider Vinegar
2 Tbs Worcestershire Sauce
1 Tsp Paprika
1 Tsp Chili Powder
Dash of Cayenne

Combine all ingredients and simmer over low heat. The longer and slower the better.