To make oven-candied walnuts, toss the nuts in a mixture of water and sugar with spices or seasonings, and then bake the walnuts for 45 minutes at 300 degrees Fahrenheit, stirring every 15 minutes. Alternatively, bake the nuts for 10 to 15 minutes at 350 degrees, watching carefully for burning.
To candy two cups of walnuts, combine 1/2 cup of powdered sugar with 3/4 teaspoon salt and any extra seasonings such as cayenne pepper for heat or cinnamon for extra spice. Stir the walnuts and four teaspoons of water into the sugar, stirring to combine all of the ingredients. Bake the nut mixture in a single layer on a baking sheet lined with parchment paper to prevent sticking and promote even cooking. Once the candied walnuts are crisp, remove the baking sheet from the oven. Allow the nuts to cool and store them in an airtight container for two to four weeks.
For a slightly lighter coating, SmittenKitchen.com recommends beating one room temperature egg white until it's frothy. Mix walnuts into the egg white and sprinkle the nuts with a combination of dark brown and white granulated sugars and salt. Bake the nuts in a single layer at 300 degrees Fahrenheit for approximately 30 minutes. Once the nuts are cool, break up any clumps.