01 - In a medium bowl or mason jar, thoroughly mix rolled oats, milk, cooled brewed coffee, packed brown sugar, Greek yogurt if using, chia seeds if desired, vanilla extract, and a pinch of salt until well incorporated.
02 - Cover the mixture and refrigerate for at least 8 hours or overnight to allow the oats to fully absorb the liquid and flavors.
03 - In the morning, stir the chilled oats well. If a creamier consistency is preferred, add a splash of additional milk.
04 - Divide the oats between bowls or jars. Top with sliced banana, toasted nuts, and extra brown sugar or maple syrup as desired. Serve chilled.