If using a microwave: In a bowl, mix together oats, cranberries and peanuts and set aside. Next, stir the butter, honey, peanut butter and brown sugar in a microwave safe bowl. Heat in 30 second increments, stirring in between, until the mixture is combined and pourable. Add vanilla to honey and peanut butter mixture and stir. Then, add honey and peanut butter mixture to dry ingredients, stirring quickly to combine. Roll the mixture into 1.5-inch balls and let cool completely. Cool and serve.