Place almond milk, dates, vanilla and cacao in blender and process until dates are pulverized. A Vitamix does a great job with this. If your blender leaves the dates too chunky, you can strain the mixture before adding it to the chia seeds.
Pour chia seeds into a medium container and add almond milk mixture. Stir immediately to combine otherwise you may end up with blobs of chia seeds. Allow to sit on countertop and stir every 5 minutes. After 15 minutes, it should have thickened.
Cover and refrigerate for at least an hour. I usually do this the night before. Stays in the fridge for as long as your almond milk would. Fun to add toppings like fresh fruit, coconut or chopped nuts.