Preheat oven to 350 degrees F (175 degrees C). Line 8 muffin cups with paper liners.
Mix white sugar, quinoa flour, oat bran, almond milk, cocoa powder, walnuts, coconut oil, egg, vanilla extract, baking soda, and kosher salt together in a bowl until batter is smooth. Let batter sit for 10 minutes to allow oat bran to absorb liquids.
Spoon batter into the prepared muffin cups.
Bake in the preheated oven until a toothpick inserted in the center comes out clean, about 20 minutes. Cool muffins in tin for 5 minutes before removing.