You can toast them quickly in a pan on a stove burner, or in the oven. To toast on the stovetop, place your 1/3 cup of peanuts into a skillet over medium heat, adding salt if desired. Toast, stirring occasionally, for 6 to 8 minutes, then transfer to a paper towel to cool. Your peanuts will be a little soft while warm, but will crisp up as they cool.