Dried minced onions are one of the best shortcuts you can use to save time in the kitchen. Add these finely minced pieces to dishes with low liquid or short cooking times, including meatloaf, gravy, dips, and savory breads or muffins. To rehydrate, simply soak in warm water for about 15 minutes, then drain. Once they’re rehydrated, they’re a flavorful substitute for fresh onions. Five teaspoons dehydrated minced onion equals about 1/4 cup rehydrated onion. Ingredients: Onion.