Banana milk is popular in quite a few places in the world. Lately I've seen it in Korean adds so I started looking around and found it's popular in Yemen. Which reminded me I had seen it in Israel and my husband used to drink it in the states in college. I'm sure they are all different versions, some with artificial flavoring and some with real bananas but this is how we make it in our house, it's not so different from the many recipes I looked at online.
For the bananas it's can be made with as many or as few as you like per pitcher but I have found that it needs quite a few to really get a good bananas flavor. How much sugar you need depends on how sweet your bananas are. For this I Like the flavor of ones that are really yellow but not any brown spots yet. Taste and add the sugar after the milk is blended to see what you need. Color too is personal preference, I wanted a little yellow color to really make it say "banana milk" but it's not necessary for anything other than aesthetics. It doesn't keep keep well so enjoy immediately.
3 c. milk
9 large bananas
2 Tbsp. sugar (optional)
Yellow food coloring
Combine the milk and bananas and blend until smooth. Add food coloring as desired and taste. Adjust sugar to taste and keep blending until the sugar is dissolved. Serve immediately.