Mash the banana: In a medium bowl or jar, mash 1/2 banana until smooth with just a few small lumps.
Add the dry ingredients: Stir in rolled oats, protein powder, cocoa powder, chia seeds, and a pinch of salt until everything is evenly mixed.
Mix in the wet ingredients: Add Greek yogurt, 1/2 cup milk, vanilla, and maple syrup or honey if using. Stir well.
The mixture should be thick but spoonable. Add extra milk a splash at a time if it feels too stiff.
Taste and adjust: If you prefer it sweeter, add a bit more sweetener. If the cocoa tastes too strong, add a little more milk or yogurt.
Chill overnight: Cover and refrigerate for at least 4 hours, ideally overnight, so the oats and chia can soften and thicken.
Stir and top: In the morning, give it a good stir. Add more milk if needed for your ideal texture.
Top with sliced banana, a spoonful of nut butter, and a few chocolate chips if you like.
Enjoy cold or warm: Eat straight from the fridge, or warm it gently in the microwave for 30–45 seconds, adding a splash of milk.