Preheat oven to 350°F and grease or line with parchment paper a 9x13 baking dish.
In a stand mixer or with hand beaters, cream together the butter and sugar until fluffy.
Add eggs, one at a time, beating well after each egg.
Mix in the vanilla extract and lemon zest.
Add the baking powder, baking soda, and 1 cup flour. Mix together on low.
Add the remaining flour and mix on low until fully incorporated.
Press ⅔ of the dough into the prepared dish and about a ½ inch up the sides.
Add the cranberries in an even single layer and gently push them into the dough a bit.
Drop slightly flattened chunks of the remaining dough over the cranberries.
Bake for 35-40 minutes until edges are golden brown and the dough no longer looks wet or glossy.
Let cool completely then glaze.
Whisk together powdered sugar, vanilla extract and milk until smooth. Drizzle over cooled bars.
Slice, serve and enjoy!