Heat oil in a medium stock pot over medium-high heat, sauté garlic and onions for approximately 3 minutes.
Add anchovy paste and parsley, sauté for 1 minute.
Add tomatoes, brown sugar and vinegar, bringing to a boil and then lowering to a simmer for 20 minutes.
Remove from heat and place contents into a blender with salt, mustard, Worcestershire and pepperoncino. Blend until smooth. Yields 2 ½ cups of sauce.
