Mix oats and brown sugar, mix in butter and vanilla. Divide mixture evenly in 2 ungreased 8-inch square pans, spread evenly. Bake at 375 degrees F. for about 10 minutes or until it looks golden-brown.

Squares will be soft, but will harden when cool. Allow to cool for 5 minutes, then mark in squares with a sharp knife. Loosen edges and allow to cool before removing from pans.