Add the plain yogurt (at room temperature) to the milk and stir until well combined.
Transfer the mixture to a heat-resistant container. Skim off any foam, cover with plastic wrap, and leave at room temperature overnight, or until the yogurt sets and thickens.
Add the mixed berry powder and mix well.
Pour the yogurt into a cheesecloth-lined strainer or bowl to remove excess liquid. Place a weight on top and refrigerate for about 1 hour, or until the desired thickness is reached.
Spoon the Greek yogurt into a serving container. Garnish with fresh fruit, grains, and drizzle with honey.