I'd frozen some overripe bananas (peeled & smooshed together in a ziploc) right after Thanksgiving, and they were perfect for the shake.
Makes 4 servings.
1 1/2-2 c frozen banana pieces
1/3 c unsweetened peanut butter
2 Tbsp raw local honey
1 tsp cinnamon
3-4 cups Coconut Milk Kefir, vanilla flavored