In a medium saucepan, combine all ingredients and whisk to combine.
Bring the mixture to a boil over medium-high heat.
Reduce the heat to low and simmer, stirring occasionally for 20 minutes until thickened.
Remove the pan from the heat and cool slightly before using.
Store in an airtight container in the refrigerator for up to one week.
NOTE: I've found that this sauce is best with the tomato sauce/ketchup mixture. The sauce does not taste like ketchup when finished. If you absolutely don't want to use ketchup, you can use a second cup of tomato sauce.NOTE: This sauce, once prepared can be stored in the refrigerator for up to one week or in the freezer for up to 3 months. If freezing, thaw in the refrigerator for at least 12 hours before using.NOTE: You can substitute light brown sugar for dark if necessary.