In a 16-ounce wide-mouth glass jar, whisk together the rolled oats, cocoa powder, chia seeds, and salt until dry components are evenly distributed.

Pour in the almond milk, maple syrup, and vanilla extract.

Stir the mixture vigorously with a spoon until the cocoa powder is fully integrated and no dry clumps remain.

Gently fold in half of the raspberries, slightly mashing a few to release their juice into the oats.

Seal the jar with a tight-fitting lid and refrigerate for a minimum of 6 hours, or ideally overnight (8 hours), to allow the oats and chia seeds to fully hydrate.

Prior to serving, stir the mixture to redistribute moisture and top with the remaining fresh raspberries and dark chocolate chips.