Using an electric hand or stand mixer, beat butter and brown sugar together in a medium mixing bowl until light and fluffy. Add eggs one at a time, mixing well between each addition.
In a separate mixing bowl combine oats, flour, baking soda and salt.
Add oat mixture to butter mixture in several additions, mixing well after each addition. Stir in dried cranberries.
Drop by rounded teaspoonfuls onto ungreased cookie sheets. Bake for 10-12 minutes or until golden brown. Cool on wire rack until room temperature.
While cookies are baking, start to make the glaze by mixing together the powdered sugar, zest and juice until evenly incorporated.
Once cookies are cooled, spoon about 1⁄2 tsp. of glaze on each cookie, spreading as desired.
Allow the glaze to harden (approximately 2 hours).