Heat oil in a large saucepan
over medium heat. Add onions and jalapenos and cook over medium heat until onions are soft and transparent, about 5 minutes. Add salt, dry mustard
, black pepper, cayenne, and garlic salt. Stir to combine and then mix in the brown sugar
. Add the cider vinegar, ketchup, molasses, Worcestershire, and water and whisk
all together until thoroughly combined. Reduce heat to low and simmer
for about 20 to 35 minutes, whisking every few minutes to prevent sauce from burning and sticking to bottom. Strain
sauce to remove onions
and jalapenos before serving.