Choose your container: Use a 12–16 oz jar or a sealable container to leave room for stirring and toppings.
Mix dry ingredients: Add rolled oats, protein powder, chia seeds, and a pinch of salt to the container.
Stir to distribute the protein powder evenly.
Add wet ingredients: Pour in milk, Greek yogurt, vanilla extract, and sweetener if using. Stir thoroughly until no dry pockets remain.
Fold in blueberries: Gently mix in the blueberries. If using frozen, add them now; they’ll thaw overnight and lightly tint the oats.
Adjust thickness: If it looks very thick, add a splash more milk.
The chia and protein will thicken it as it rests.
Cover and chill: Seal and refrigerate for at least 4 hours, but overnight is best for maximum creaminess.
Serve: In the morning, stir, taste, and adjust sweetness. Top with more blueberries, a sprinkle of nuts, or a spoonful of yogurt if you like.