Add frozen banana slices, pineapple (optional), lesser amount of coconut milk (3/4 cup or 180 ml as original recipe is written // adjust if altering batch size), matcha powder, and spinach to a blender and blend on high until creamy and smooth.
Add only as much coconut milk as you need to help it blend. In my opinion, you want this smoothie somewhere between scoopable and drinkable.
Taste and adjust flavor as needed, adding more banana (or a touch of maple syrup or stevia) for sweetness, matcha for more intense green tea flavor, or coconut milk for creaminess (though adding more matcha powder adds more caffeine, so use your best discretion). Pineapple will add a little tart/tang, so add more if desired.
Divide between two serving bowls (amount as original recipe is written // adjust if altering batch size) and top with desired toppings (optional). I went with fresh raspberries, chia seeds, and coconut flake. Bananas would make a delicious garnish as well.
Best when fresh, though leftovers keep well sealed in the refrigerator up to 24 hours.
*Thin with water instead of coconut milk to save on calories, if desired. *Nutrition information is a rough estimate.