Preparation Steps

• Preheat the oven to 350°F (175°C). Line a 9x5-inch loaf pan with parchment paper leaving a 1-inch overhang on the long sides, then lightly grease the parchment with a little coconut oil.
• In a medium bowl mash the ripe bananas with a fork until mostly smooth. Stir in the Greek yogurt, maple syrup, melted coconut oil, eggs and vanilla until evenly combined.
• In a large bowl whisk together the protein powder, whole wheat flour, all-purpose flour, baking soda, baking powder, salt and ground cinnamon so there are no lumps and the leavening is evenly distributed.
• Pour the banana-yogurt mixture into the dry ingredients and fold gently with a rubber spatula until just combined — avoid overmixing. The batter should be thick but spreadable.
• Fold in the chopped walnuts with a few quick turns. Let the batter rest for 8 to 10 minutes so the protein powder and flours hydrate; this improves texture and prevents a gummy crumb.
• Spoon the batter into the prepared loaf pan and smooth the top. If you like, press a thin banana slice or two into the center for a decorative top.
• Bake for 45 minutes, then check the loaf. If the top is browning too quickly, tent loosely with foil and continue baking another 5 to 10 minutes, or until a toothpick inserted into the center comes out clean or with a few moist crumbs.
• Remove the pan from the oven and cool on a wire rack for 10 to 15 minutes. Use the parchment overhang to lift the bread from the pan, then cool another 20 minutes before slicing so the crumb sets.
• Slice and serve warm or at room temperature. Store leftovers wrapped at room temperature for 2 days or refrigerate up to 5 days; slices can also be frozen for up to 3 months.