01 - In a medium mixing bowl, add rolled oats, milk, Greek yogurt, Biscoff spread, maple syrup or honey (if desired), vanilla extract, and salt. Mix thoroughly until the spread is fully incorporated and the mixture is smooth and uniform.
02 - Evenly distribute the oat mixture between two clean glass jars or airtight food storage containers, leaving about half an inch of space at the top for toppings.
03 - Seal containers tightly with lids and place in the refrigerator. Let chill for a minimum of 6 hours, ideally overnight, allowing the oats to soften and absorb the liquid and flavors completely.
04 - The next morning, give the oats a thorough stir to reincorporate any separated liquid. Top generously with crushed Biscoff cookies, drizzle with melted Biscoff spread, and add fresh banana slices or berries if using. Enjoy cold directly from the jar.