Freeze the banana ahead of time if possible (recommended): peel and break the banana into chunks and freeze for at least 2 hours. Freezing the banana thickens the bowl and gives it a creamy, ice-cream-like texture without diluting flavor. If you don't have a frozen banana, use fresh banana and add the optional ice cubes when blending.

Layer the blender or high-speed processor: add the liquid (1/2 cup water or milk) first, then the Greek yogurt, followed by the spinach, frozen banana, rolled oats, and a pinch of salt. Adding liquid first helps the contents circulate so the blades catch leafy greens and eliminate stubborn pockets of spinach; the salt brightens the flavors.

Pulse 10–15 seconds to break down larger pieces, then blend on medium-high for 20–40 seconds until smooth. Start with short pulses to chop the spinach and oats evenly, then blend continuously to create a uniformly creamy base—over-blending will warm the mix slightly, so stop when smooth and still cold.

Taste and adjust: if the bowl is too thick, add 1–2 tablespoons of water or milk and pulse once; if too thin, add a few more frozen banana pieces or 1 tablespoon more oats and pulse. Balancing thickness is crucial because a smoothie bowl should be ladle-able but spoonable—thicker than a drinkable smoothie so the toppings stay on the surface.

Divide the green base between two bowls. Spoon each portion into a bowl and use the back of the spoon to create a shallow well in the center—this helps you place the peanut butter and toppings attractively, creating a restaurant-style presentation.

Warm the peanut butter briefly (10–15 seconds) in a small microwave-safe bowl or by immersing the jar in warm water. Warming loosens the peanut butter so you can make a glossy swirl without breaking the bowl's surface. Drizzle 1 tablespoon over each bowl and use a toothpick or spoon to create a swirl pattern for a professional look.

Add toppings for texture and brightness: scatter 1/4 cup mixed berries over each bowl, and if you like, sprinkle a few extra rolled oats or seeds for crunch. The cold berries add bright acidity that balances the sweet banana and rich peanut butter, while oats add a chewy contrast.

Final finishing: press a few whole spinach leaves or edible microgreens on the side of the bowl for color, and drizzle a tiny extra pinch of peanut butter or a few whole oats across the top. Serve immediately—smoothie bowls are best enjoyed right away while cold and textured.