Preheat oven to 325 and grease an 9x13 inch pan. In a small bowl combine flour, oats, cinnamon, brown sugar and salt. Stir in melted butter and orange juice. Press into prepared pan.
Mix together greek yogurt and sugar. Stir in flour, vanilla, cinnamon, and egg white and mix well. Gently stir in Craisins and optional white chocolate chips. Spread filling over crust.
Mix together oats, flour, sugar, and cinnamon. Cut in chilled butter with pastry knife or two forks. Crumble topping over filling. Bake about 40 minutes or until filling is set. Cool and cut into bars. Store in airtight container.