Combine the base ingredients: In a medium saucepan, whisk together yellow mustard, apple cider vinegar, and brown sugar until smooth.Add flavor boosters: Stir in garlic powder, onion powder, paprika, salt, and black pepper. Mix thoroughly.Simmer and reduce: Place over medium heat and bring to a gentle simmer. Reduce heat to low and cook for 10–15 minutes, stirring occasionally.Taste and adjust: Add more vinegar for tanginess, or honey for sweetness as needed. Adjust seasoning to your preference.Cool and store: Remove from heat, let cool, and store in an airtight jar in the refrigerator for up to 2 weeks.