01 - Preheat the oven to 350°F. Line a 12-cup muffin tin with paper liners or lightly grease each cup with cooking spray.
02 - In a large bowl, whisk together the eggs, milk, protein powder, maple syrup, cinnamon, vanilla extract, and salt until completely smooth and well combined.
03 - Add the bread cubes to the egg mixture, tossing gently until the bread is well coated and has absorbed most of the liquid. Allow the mixture to sit for 5 minutes.
04 - Divide the soaked bread mixture evenly among the 12 muffin cups, pressing down lightly to compact the bread cubes.
05 - Sprinkle your choice of toppings (nuts, chocolate chips, or berries) over each muffin.
06 - Bake for 20 to 25 minutes, or until the muffins are puffed, golden brown, and set in the center.
07 - Let cool for a few minutes before removing from the tin. Serve warm or at room temperature.