Spiced Banana Yogurt Muffins

Name: Spiced Banana Yogurt Muffins
Ingredients: 2 bananas; 200 grams plain Greek yogurt (I use full-fat); 2 large eggs; 75 grams melted coconut oil; 145 grams dark brown sugar; 2 teaspoons dark rum (optional but highly encouraged); 1 teaspoon vanilla; 142 grams gluten-free flour blend (I use Trader Joe's); 48 grams almond meal; 1 teaspoon salt; 1 teaspoon baking soda; 2 teaspoons cinnamon; 0.5 teaspoons nutmeg; 0.5 teaspoons ground allspice; 1 pinch cardamom; 70 grams chopped walnuts (optional)