01 - In a medium mixing bowl or a mason jar, thoroughly combine rolled oats, milk, brewed coffee, brown sugar, Greek yogurt if using, chia seeds if using, vanilla extract, and a pinch of salt. Stir until all components are evenly blended.
02 - Cover the container with a lid or plastic wrap and refrigerate for at least 8 hours, allowing flavors to meld and oats to absorb the liquid.
03 - Upon removal from the refrigerator, stir the oats well and, if preferred, incorporate a small splash of additional milk to reach desired creaminess.
04 - Portion the oat mixture into serving bowls or jars. Garnish with sliced banana, toasted nuts, and extra brown sugar or maple syrup to taste.
05 - Enjoy immediately, served chilled.