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