In a large bowl or two individual mason jars, combine oats, milk, Greek yogurt, mashed banana, honey, vanilla extract, pudding mix (if using), and salt.
Stir everything together until well combined. The mixture should be creamy and well-mixed.
Divide between two jars or containers if not already portioned. Cover and refrigerate for at least 8 hours or overnight.
In the morning, give the oats a quick stir. Top with sliced banana, crushed cookies, and a dollop of whipped cream if desired.
Drizzle with additional honey and enjoy immediately, or grab and go for a perfect portable breakfast.