Preheat oven to 350℉. Make parchment circles for the muffin pans, spray with non-stick spray and set aside.
To brown the butter, start by melting it in a saucepan over low heat. Initially, the butter will foam and bubble. When the foam, which consists of milk solids, turns brown and settles at the bottom of the pan, and the aroma becomes nutty with only sporadic popping sounds, take the butter off the heat. Pour it into a heatproof bowl and let it cool to room temperature until it solidifies. To quicken the cooling process, you can place it in the refrigerator.
Blend your bananas in a bowl using a hand mixer until smooth. If you prefer a more textured banana muffin, simply use a fork to mash them until no chunks larger than a blueberry remain. Set aside once done.
Combine the flour, baking soda, cardamom, and salt in a medium-sized mixing bowl. Whisk for around 30 seconds, or until everything is distributed evenly. Set aside.
Put the browned butter and brown sugar into the bowl of a stand mixer equipped with the paddle attachment. Cream them together until they become light and fluffy, which should take around 5 minutes.
Clean the sides of the bowl. Introduce the eggs one at a time, ensuring each one is fully blended before adding the next. Scrape the sides of the bowl again, then mix in the yogurt, mayonnaise, and vanilla extract until everything is evenly combined. Finally, add the flour mixture and stir until just mixed.
Take the bowl off the mixer, mix the apple cider vinegar into the bananas, and then gently fold them into the batter. Pour the batter into your prepped muffin pans and bake for 20-25 minutes, or until a toothpick or cake tester inserted into the middle of a muffin comes out clean.
