Preheat oven to 350°F / 175°C. Line or lightly grease a 9-inch x 5-inch loaf pan.
In a medium bowl, mix together the mashed bananas, milk, brown sugar, and vanilla extract. You can mix this by hand, or use a hand mixer on low speed. I usually use a hand mixer since I find that it quickly will mash/puree a ripe banana. As you are mixing, slowly pour in the coconut oil and mix it in.
In a separate large bowl, whisk together the flour, baking powder, baking soda, cinnamon and salt.
Add the wet ingredients into the dry ingredients and mix together until just combined. Stir in the vinegar.
Pour the batter into the prepared loaf pan. Top the batter with the oats and turbinado sugar.
Bake the banana bread, rotating halfway through, until a tester inserted into the center comes out clean, 45-55 minutes. Transfer pan to a wire rack and let the banana bread cool in pan 5 minutes. Transfer the banana bread onto a rack and let cool completely.
Store in an airtight container for 2 days.Dairy-Free banana bread: You can replace the milk with a milk alternative of your choice. As my son is also intolerant to dairy, we use Oatly Oat Milk, and have had great success baking and cooking with Oatly.Low sugar banana bread: You can use anywhere between ¼ cup - 1 cup sugar for this recipe. I don't like too much added sugar in our diet, particularly when I'm making these muffins for my toddler, so I typically make this banana bread with ¼ cup sugar, and sometimes even less. Instead, try using a ripe banana for natural sugars and flavor. However, if I'm bringing these to a potluck, or sharing it with friends, to make the recipe taste more like a sweet banana bread you might get at a coffee shop, I would recommend using up to the full 1 cup of sugar.