Preheat oven to 375 degrees F.
In a large mixing bowl, cream together butter and sugars until fluffy, approximately 1 minute.
Add egg and vanilla, and mix until just combined.
In a medium mixing bowl, combine flour, oats, baking powder and soda, and salt, and stir to distribute evenly.
Add dry ingredients to wet ingredients.
Stir together until combined.
Add white chips and dried cranberries and stir until combined.
Drop 1 inch cookie dough balls onto cookie sheet about 2 inches apart.
Bake 7-8 minutes, or until cookies are set in middle and are just beginning to turn golden brown around the edges.
Remove from oven and let sit on baking sheet for 2 minutes before removing to cooling rack.