In a blender, combine the rolled oats, skim milk, low-fat yogurt, stevia powder, and vanilla extract.
Blend on medium speed until all the ingredients are well combined and you achieve a smooth and creamy consistency.
Transfer the blended mixture to a jar or container with a lid.
Cover the jar/container and refrigerate overnight, or for at least 4 hours, to allow the oats to soften and the flavors to meld together.
Before serving, give the mixture a good stir to ensure it's well mixed.
To serve, top the blended overnight oats with a generous amount of mixed berries.
Enjoy your delicious and nutritious blended overnight oats as a satisfying breakfast or snack.