Place flour into a microwave-safe bowl, and heat in the microwave for 40 seconds. In a large bowl, combine softened butter with sugar until fluffy. Add in milk, and mix until smooth.
Add in the heated flour, and mix until a thick dough forms. Fold in dried cranberries, and white chocolate chips. Place the cookie dough onto half of the pretzels.
Sandwich with the remaining pretzels. Refrigerate until serving.