Place a small skillet over medium heat. Add the coconut oil, maple syrup, cinnamon, and a tiny pinch of salt.
Add the banana slices in a single layer. Let them cook for about 2–3 minutes on each side until soft, golden, and lightly caramelized.
Transfer the bananas to a plate. Add the chopped walnuts or pecans to the same skillet and toast them for about 1 minute until fragrant.
In a bowl, stir together the Greek yogurt and vanilla protein powder until smooth and creamy.
Spoon the yogurt mixture into a serving bowl.
Top with the warm caramelized bananas and toasted nuts.
Finish with a drizzle of peanut butter and a sprinkle of flaky sea salt if desired. Serve right away while the bananas are still warm.