Whisk the dry ingredients. In a jar or bowl, combine the chia seeds, cocoa powder, and a pinch of salt.
Whisk well to break up any cocoa clumps.
Stir in the liquids. Add the milk, maple syrup (or honey), and vanilla. Whisk until the cocoa looks fully dissolved and the mixture is smooth.
Rest and whisk again. Let the mixture sit for 5 minutes, then whisk once more to prevent clumping. This step helps the chia seeds distribute evenly.
Chill overnight. Cover and refrigerate for at least 3 to 4 hours, but ideally overnight, until thick and pudding-like.
Adjust and serve. In the morning, give it a good stir.
If it’s too thick, add a splash of milk. Taste and adjust sweetness if needed. Top with fruit, nuts, or a dollop of yogurt.