Grandma's Homemade BBQ Sauce is my grandma's tried and true recipe for an easy to make sweet and tangy BBQ sauce!
Set a large pot over medium to medium low heat. Add the olive oil and onions. Cook 12 to 15 minutes, stirring a few times. They should be soft and tender, not brown, so lower heat as they cook if needed.
Season with kosher salt, garlic powder, and onion powder. Add the chili sauce, ketchup, sugar, water, vinegar, Worcestershire sauce, yellow mustard, and horseradish.
Let this simmer over medium low heat for an hour or more, stirring a few times.
Taste for seasoning and add more kosher salt, garlic powder, and/or onion powder if needed.
Note: This recipe can be doubled, and leftovers can be stored in the freezer in a covered container for up to 3 months.