Preheat oven to 250°. In a large bowl combine oats, walnuts, and coconut. In a small bowl, whisk balsamic, olive oil, and brown sugar until sugar is dissolved. Poor over oat mixture tossing to thoroughly coat. Beat the egg whites in a small bowl until fluffy, add to granola, and mix to evenly coat. Spread out onto a baking sheet lined with parchment paper. Bake for 40-50 minutes until golden brown, stirring every 10 minutes. Remove from oven as soon as the oats become golden brown. Add cranberries once granola has cooled. Store in airtight container.