Mash or blend the bananas until smooth. Mix them with the Greek yogurt, milk, rolled oats, chia seeds, and vanilla extract. Do not add the blueberries yet.
Divide the mixture between two bowls, jars, or airtight containers. Cover and refrigerate overnight.
Just before serving, top each portion with 50 g/ 1.76 oz. of fresh blueberries.
Tips
You can replace the chia seeds with 4 tbsp rolled oats or 3 tbsp shredded coconut.
Instead of vanilla extract, use ½ tsp ground cinnamon.
I like my overnight oats thick and creamy. If you prefer a thinner consistency, simply add a little more milk or leave out the chia seeds.
How to store
Store covered in the refrigerator for up to 2 days.