Step 1

In a small, 1 1/2-quart (1.5 l) saucepan, combine the garlic, cayenne (or pepper flakes), pho spice blend, rice flour, tahini, vinegar, water, miso, and sugar. Whisk or vigorously stir to combine well. Because miso varies so much in flavor, add up to 1 tablespoon of miso if the mixture is too mild or mellow.

Step 2

Bring to a simmer over medium heat and cook, stirring occasionally, until thickened, about 1 minute. Let cool and concentrate off heat for 15 minutes; whisk or stir occasionally to prevent a skin from forming. Taste and, if needed, add soy sauce by the teaspoon or vinegar by the 1/2 teaspoon.

Step 3

If the mixture is smooth, strain through a mesh strainer, discarding the garlic. If the mixture is chunky from the miso, puree it in a food processor. The flavors open up overnight, though you can enjoy the sauce right away. Keep refrigerated in a jar for up to 3 months, bringing to room temperature before using.