Preheat oven to 350 degrees. Line baking sheets with silicone baking mats or parchment paper.
In a large mixing bowl, cream the butter, brown sugar and granulated sugar until light and fluffy, about 2–3 minutes. Beat in the eggs and vanilla.
In another bowl, combine the oats, flour, baking soda and salt. Gradually add to the butter mixture, folding in the last of it by hand. The dough will be thick.
Fold in the white chocolate chips and dried cranberries.
Cover and chill the dough for 30 minutes (recommended for thicker cookies).
Scoop the dough with a medium cookie scoop onto the prepared sheets, about 2 inches apart (about 12 per sheet).
Bake for 9–12 minutes, until the edges are golden and the centers look slightly underdone. Cool on the pan for 3–5 minutes, then transfer to a cooling rack.