Preheat the oven to 350 degrees Fahrenheit.
Add 3 large ripe bananas to a large mixing bowl, then use a potato masher or fork to mash them well.
Add 1 cup unsweetened milk of choice, 1/3 cup cocoa powder, 1/4 cup maple syrup, 1 teaspoon pure vanilla extract, 1/4 teaspoon salt, and 1 teaspoon apple cider vinegar to the mixing bowl, then mix well.
Add 1/3 cup melted coconut oil, then mix well (be sure to mix immediately after adding the coconut oil to prevent it from solidifying).
Add 1 3/4 cups buckwheat flour and 1 teaspoon baking soda, then mix well.
Divide the batter evenly into a 12 cup muffin pan lined with paper baking cups.
Bake for 28 minutes or until a toothpick inserted into the center of a muffin comes out looking clean.
Let cool before serving.