Butterscotch brownies aren't technically brownies - they're blondies. True brownies use chocolate. Oh, I suppose you could make brownies with butterscotch swirled in or with butterscotch chips and call it a butterscotch brownie.
Traditional butterscotch brownies are relatively easy to make and don't require any butterscotch chips. Still, some recipes do call for butterscotch chips and those are a fairly gauranteed way to make sure you get the flavor right. Butterscotch brownies, or blondies, have a more cookie-like texture than regular brownies. CakeSpy has an excellent write-up of brownies vs blondies. (Plus, the photos there are adorable!) None of the recipes linked so far your style? Check out CDKitchen - there's a list of butterscotch brownie recipes where you should be able to find one you're interested in. The Los Angeles Times shares a recipe from the restaurant Clementine. Or you can try making butterscotch brownie swirls - those are sure to impress at your next party. Want to change things up a little bit? Try adding Baileys, apples or try going for a tart form.