Whisk the base: In a medium bowl, whisk milk, cocoa powder, sweetener, vanilla, and salt until the cocoa dissolves completely. If using protein powder, whisk it in now. A small hand whisk or milk frother helps remove lumps.
Add chia seeds: Sprinkle chia seeds over the liquid and whisk for 30 seconds to distribute evenly.
Let it sit for 5 minutes, then whisk again to prevent clumping.
Portion into jars: Divide the mixture between two small jars or one large jar. If adding nut butter or yogurt, you can swirl it in or layer it later.
Chill: Cover and refrigerate at least 2 hours, preferably overnight. The chia will absorb the liquid and thicken into a pudding.
Stir and adjust: Before eating, give it a quick stir.
If it’s too thick, add a splash of milk. If it’s not sweet enough, drizzle a bit more syrup.
Top and serve: Finish with sliced banana, berries, nuts, cacao nibs, or granola for texture and freshness.