Add the sliced bananas, peanut butter, cinnamon, and milk into the blender.
Secure the lid and blend on high until the mixture is smooth, thick, and creamy. You should see a consistent texture with no lumps, and the mixture will be fragrant with cinnamon aroma.
If desired, add oats, chia seeds, or a drizzle of honey to boost flavor and nutrition, then blend briefly to incorporate.
Pour the smoothie into glasses, observing its thick, velvety texture and inviting color.
Optionally, top with sliced bananas, a sprinkle of cinnamon, or granola for added crunch and visual appeal.
Enjoy immediately with a straw or spoon for a nourishing, comforting treat that’s perfect for busy mornings or an energizing snack.