Add all of the ingredients to a mixing bowl. Whisk well to combine. Taste, adding a pinch of salt or pepper as needed. For more sweetness, add a bit more maple syrup. For more smokiness, add a few drops more of liquid smoke or a few dashes of smoked paprika.
Transfer the BBQ sauce to a small frying pan and simmer for 3 to 5 minutes, stirring at least once a minute.***Take off the heat. Once cool, transfer to an airtight jar and refrigerate. It will thicken as it chills. Store for 7 to 10 days.
To thicken the sauce even more, whisk together arrowroot powder and cold water until smooth and no clumps remain. Add the slurry to the simmering sauce (from step 2) and whisk frequently for 1-2 minutes, or until the sauce is thickened. Take off the heat (don't let it keep simmering, or the arrowroot powder can start to congeal).
*See the "ingredients and substitutions" section in the blog post for vegan-friendly Worcestershire sauce brands. Or, try my homemade blend (included in the blog post). ** If you don't have liquid smoke, add more smoked paprika. Start with an additional 1/2 teaspoon and use up to 1 1/2 teaspoons. *** If you are making the BBQ Tempeh recipe, you do not need to simmer the sauce for this long. Just 1-2 minutes is fine.