In a medium-sized jar or bowl, add rolled oats and brown sugar. Pour in milk and mix well until fully incorporated. If using, add yogurt now and stir until integrated.

Seal the jar or cover the bowl and refrigerate overnight, ideally for at least 4 hours.

In the morning, remove from the fridge, stir well, and add a splash of milk if too thick.

Top with fresh fruits and nuts, and add honey or cinnamon if desired.