Combine all ingredients in a heavy-bottomed pot, like an enameled cast iron pot, and whisk to thoroughly combine.

Bring to a boil over medium high heat, then reduce heat to medium / medium-low. Simmer for 30 minutes until reduced and thickened, stirring frequently with a rubber spatula, scraping the bottom and sides of pot.

When sauce is desired consistency, remove from heat and cool completely before storing in an airtight container in the refrigerator for up to 2 weeks.