Add liquids first. Pour the milk into your blender.
This helps the blades catch and blend smoothly.
Layer the creamy ingredients. Spoon in the yogurt and peanut butter. Add the vanilla and a pinch of salt if using.
Pile on the fruit. Add the banana and frozen berries. If you want a thicker texture, use more frozen berries or a frozen banana.
Sweeten to taste. Drizzle in honey or maple syrup if your berries are tart or if you prefer a sweeter smoothie.
Blend until smooth. Start on low and increase to high for 30–60 seconds, until creamy and well combined.
Add a splash more milk if it’s too thick, or an ice cube if you want it frostier.
Taste and adjust. If it needs more peanut butter for richness, add a teaspoon or two and blend again. If the berry flavor is too subtle, add a few more berries.
Serve right away. Pour into a glass and enjoy. For a fun touch, swirl a tiny ribbon of peanut butter on the inside of the glass before pouring.