In a medium bowl or storage container, stir together 1 cup rolled oats, 1 tablespoon chia seeds, ⅔ cups milk, ⅓ cup strong brewed coffee (warm or cooled), 2 tablespoons maple syrup, and 1 teaspoon vanilla extract until well combined. Cover and refrigerate overnight, or for at least 4 hours.
Shortly before serving, in a small bowl, stir together ¾ cup Greek yogurt, 1 tablespoon maple syrup, and ½ teaspoon vanilla extract until smooth.
Give the oats a good stir. If they seem too thick, add a splash of milk. Divide the oats between two jars or bowls. Top with the yogurt mixture and dust generously with 1 tablespoon unsweetened cocoa powder. Serve cold.
