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 mixing bowl, whisk together the eggs, milk, protein powder, maple syrup, cinnamon, vanilla extract, and salt until completely smooth and no powder lumps remain.
03 - Add the bread cubes to the egg mixture. Fold gently until all bread pieces are evenly coated and have absorbed most of the liquid. Allow the mixture to rest for 5 minutes to ensure full absorption.
04 - Divide the soaked bread mixture evenly among the 12 prepared muffin cups. Press down lightly with a spoon to compact the mixture in each cup.
05 - Sprinkle your choice of toppings (pecans, walnuts, chocolate chips, or fresh berries) evenly over the top of each muffin.
06 - Bake for 20 to 25 minutes, or until the muffins are puffed, golden brown on top, and set firmly in the center. A toothpick inserted into the center should come out clean.
07 - Allow the muffins to cool in the tin for 5 minutes before removing. Serve warm or at room temperature. Store leftovers in an airtight container in the refrigerator for up to 4 days.