Place the 1 cup cold water, ¾ cup yellow dry mustard powder, ¾ teaspoon coarse sea salt or kosher salt, ½ teaspoon ground turmeric, 1 teaspoon garlic purée, and ⅛ teaspoon paprika in a small nonreactive saucepan and whisk until smooth.
Cook the mixture over medium-low to low heat, stirring often, until it bubbles down to a thick paste, 30 to 45 minutes.☞ TESTER TIP: You’re definitely going to want to do this in a well-ventilated kitchen. Trust me. And that nonreactive saucepan is also essential or the mustard could take on an off color and hue.
Whisk the ½ cup white distilled vinegar into the mustard mixture and continue to cook until it’s thickened to the desired consistency—you know, the usual prepared mustard consistency—which can take anywhere from 7 to 15 minutes.
Let the mustard cool to room temperature before spooning the mustard into an airtight container. Cover and refrigerate for up to 3 months. ☞ TESTER TIP: The mustard will be quite pungent the first few days or even weeks, but will mellow with time.
