Prep: Preheat oven to 175°C (350°F). Line 1.9L loaf pan with parchment.
Flax Egg: Mix flaxseed + water; let thicken 5 mins.
Combine Wet: Whisk bananas, oil, milk, flax mix, vanilla, and vinegar until smooth.
Mix Dry: Sift flour, sugar, baking soda/powder, spices, and salt in separate bowl.
Batter: Fold wet into dry until *just combined* (overmixing = dense bread). Add mix-ins.
Bake: Pour into pan. Bake 55-65 mins until skewer comes clean. Cool 15 mins before slicing.