In a small sauce pan, heat oil over medium-high. Add shallot and cook, stirring often until softened, 3 minutes. Add vinegar and cook until slightly evaporated, 1 minute. Add mustard and brown sugar; stir until warm and combined. 1 minute. Season with salt and pepper and remove from heat. Refrigerate cooled glaze in airtight container, up to 1 day.
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