01 -  Preheat oven to 350°F. Lightly grease a 9x13-inch baking dish with nonstick spray. 
 02 -  Arrange bread cubes evenly in the prepared dish, then evenly scatter blueberries over the bread. 
 03 -  In a blender, combine milk, cottage cheese or Greek yogurt, eggs, protein powder, maple syrup, vanilla extract, cinnamon, and salt. Blend until a smooth consistency forms. 
 04 -  Pour the blended mixture evenly over bread and blueberries. Lightly press down to help bread absorb the liquid thoroughly. 
 05 -  Sprinkle chopped nuts and sugar on top if using. 
 06 -  Cover with foil and bake for 30 minutes. 
 07 -  Remove foil and continue baking for an additional 10 minutes, or until puffed and golden. 
 08 -  Let cool briefly before serving. Serve warm, optionally with extra maple syrup.