Heat oven to 350. Lightly spray a 9" x 13" baking dish w/ cooking spray. In a lg bowl, beat butter and brown sugar.
Add oats to bowl, along w/ 1-1/2 cups flour, mix well. Set aside 1-1/2 cups of mix for topping. Press remaining mix into bottom of baking dish. Bake for 10 mins.
In another lg bowl, combine cranberries, sugar, sour cream, egg, lemon peel and vanilla. Add remaining flour. Mix well. Spread berry mix over crust. Sprinkle w/ reserved topping mix. Bake 25 mins or until light golden brown. Cool. Cover and chill for 1/2 an hour. Cut into bars.