Line a loaf pan with parchment paper (unless using a silicone pan).
Mix all ingredients well.
Pour into pan and bake for about 40 minutes, until firm and bread is just beginning to brown.
Remove from oven, and let cool.
Slice and enjoy! Store in the refrigerator.
Notes
A note about substitutions: because each type of protein powder has a distinct flavor and texture when baked, I would not try substituting different types of protein powders in this recipe. (See my Recipe Basics video for examples of what goes wrong when you use the wrong protein powder.) My loaf pan is 8.5 x 4.5 x 2.5 in. For larger loaf pans, you might want to scale up the recipe.