Frozen corn is a must-have freezer staple. The golden kernels can upgrade just about any dish, and they take center stage in this crowd-pleasing condiment. Along with corn, the recipe includes red onion, bell pepper, and mustard seeds for deep savory flavor, and theres enough sugar in the mix to round out the tart apple cider vinegar. Serve on a cheese plate, dolloped on a grilled fish taco, or spooned over seared pork chops.