• 1/2 cup dry mustard powder , preferably one 2-ounce container Coleman's
• 1/2 cup apple cider vinegar
• 2 large egg yolks
• 1/2 cup packed light brown sugar

Whisk mustard powder and vinegar together in a small bowl. Cover and refrigerate overnight.

Whisk yolks and brown sugar into mustard mixture. Transfer to the top of a double boiler and place over simmering water. Cook, whisking constantly, about 8 minutes, until thickened and an instant-read thermometer registers 160°. Remove from heat, cool to room temperature, and chill, covered, until ready to use. (Mustard may be made up to 1 month ahead.)

Adapted from Back to the Table by Art Smith