Preheat your oven to 350°F (175°C). This ensures your donuts bake evenly.
Lightly grease your donut pan with cooking spray or line it with parchment paper to prevent sticking.
In a large mixing bowl, whisk together the flour, chocolate protein powder, cocoa powder, baking powder, and salt until well combined.
In another bowl, mix together the peanut butter, water, yogurt (or mashed banana), and maple syrup (or honey) until smooth and creamy.
Pour the wet ingredients into the dry ingredients. Stir gently until just combined, being careful not to overmix.
Using a spoon or piping bag, fill the donut pan with the batter, filling each mold about 3/4 full.
Place the donut pan in the preheated oven and bake for 10-12 minutes, or until a toothpick inserted into the center comes out clean.
Remove the donuts from the oven and let them cool in the pan for about 5 minutes before transferring them to a wire rack to cool completely.
