Add the frozen banana slices to the blender. They should be firm but yield slightly when pressed, and add a creamy base to the smoothie.
Scoop in the peanut butter, feeling the smooth, slightly oily texture that contributes to the rich, nutty flavor.
Pour in the milk, observing how it begins to loosen the mixture and create a liquid foundation for blending.
Add the vanilla extract and a pinch of cinnamon to the blender, giving the mixture a warm aroma and flavor.
Blend on high for about 30-45 seconds until the mixture is velvety, smooth, and completely combined, with no visible banana chunks or peanut butter streaks.
Stop the blender and check the texture. If it’s too thick, add a splash more milk and pulse again; if too thin, add another frozen banana and blend briefly.
Taste the smoothie and, if desired, add a touch of honey or more vanilla for extra sweetness, then give it a quick blend to incorporate.
Pour the smoothie into glasses, watching it pour in a thick, inviting stream with a warm, creamy hue. Optionally, garnish with a sprinkle of chopped nuts or a drizzle of honey for visual appeal.
Serve immediately while frothy and chilled, or refrigerate in an airtight container for up to 24 hours, giving it a quick stir before enjoying.