Begin by breaking dark chocolate into small pieces and microwaving in short bursts until smooth.

In a mason jar, combine oats, milk, Greek yogurt, chia seeds, cocoa powder, and vanilla extract. Add maple syrup and melted chocolate, then stir well.

Gently fold in chocolate chips evenly into the mixture.

Seal the jar and refrigerate overnight or for at least 4 hours.

Stir well before serving and add toppings as desired.