Because they're usually made up of 7 layers: butter, graham crackers, coconut, nuts, chocolate chips, white chocolate chips, and sweetened condensed milk. The great thing about Seven Layer Bars, though, is that you can totally customize them to your liking. Add other candy and make 8 layer bars, layer on your favorite drizzle and make 9 layer bars, leave out the nuts and make 6 layer bars, you really can't go wrong!