Blend the base: Add ½ cup blueberries, 1 cup Greek yogurt, ½ cup milk, 2 tablespoons maple syrup, ½ teaspoon cinnamon, and 1 teaspoon vanilla extract to a bowl. Blend with an immersion blender until smooth. (Or blend in a regular blender, then pour into a bowl.)
Add the chia: Add 3 tablespoons chia seeds. Whisk for about 30 seconds to break up any clumps. Cover the bowl, or divide the mixture into small jars. Refrigerate for at least 2 hours, or overnight, until thick and creamy.
Stir and serve: Stir before serving to make it extra creamy. Top with extra blueberries, nuts, or a drizzle of maple syrup if you like. Enjoy cold, or warm gently in the microwave for a few seconds.
