Preheat the oven to 350℉. Grease a 7.5 x 10.5 inch pan.
Cut or tear bagels into bite-sized pieces. Spread bagel pieces evenly into the pan. Sprinkle with cinnamon.
In a bowl, combine eggs, egg whites, greek yogurt, brown sugar, and vanilla extract. Whisk very well.
Pour egg mixture over the bagels.
In a small bowl, mix together the granulated sugar and cinnamon. Sprinkle the dish with cinnamon sugar mixture.
Cover with foil and bake for 45 minutes. Remove foil and bake until golden brown and eggs are cooked through. This should take about 25 more minutes.
Allow to cool before cutting. Store in containers for the week.