Assemble the overnight oats: In a jar or container that will hold 1 ½ cups, add the oats, chia seeds, espresso powder, and salt. Stir together to combine. Add the milk, maple syrup, rum (if using), and vanilla. Stir well and top with a lid.
Chill: Place in the fridge and chill overnight, or at least 8 hours. The oats will keep for 4 days refrigerated.
Top and enjoy: Unscrew the lid and give the oats a stir. Top with a generous dusting of cocoa powder and a big dollop of Greek yogurt. Sprinkle with mini chocolate chips, if desired. Love the recipe? Leave us stars and a review below!
