Hawaij Spiced Rye Banana Bread

Name: Hawaij Spiced Rye Banana Bread
Ingredients: For the bread; 3 ripe bananas, mashed + 1 whole, for the top; 100 grams (1 cup) rye flour, or any other flour you’d like; 70 grams (1/2 cup) plain flour; 1 teaspoon bicarbonate of soda; 1 teaspoon baking powder; 2 teaspoons Hawaij spice mix (recipe follows - check notes); 1/2 teaspoon salt; 200 grams (1 cup) brown sugar, loose; 60 milliliters (1/4 cup) vegetable oil; 60 milliliters (1/4 cup) whole milk + 1/2 teaspoon vinegar (leave this mixture for 10 minutes to curdle, or use the same amount of buttermilk or yoghurt); 1 egg; For the Hawaij Spice Mix; 1 tablespoon ground ginger; 1 tablespoon cardamom; 1/4 teaspoon each: cloves, cinnamon, nutmeg