In a large bowl, whisk together the yogurt, milk, chia seeds, both cocoas, honey, scraped vanilla beans and salt until combined. Cover the bowl with plastic wrap and place it in the fridge to chill and thicken, for about 4 hours or even overnight. I usually go back and stir the mixture a few times while it sits to stir out any lumps. You also might want to take a little taste to see if you’d like it to be sweeter.