Moist Spiced Banana Cake

Ingredients

• 2 cups all-purpose flour
• 1 teaspoon baking powder
• 1 teaspoon baking soda
• 1/2 teaspoon salt
• 1 teaspoon ground cinnamon
• 1/2 teaspoon ground nutmeg
• 1/4 teaspoon ground cloves
• 1/2 cup unsalted butter, softened
• 1 cup granulated sugar
• 1/2 cup brown sugar, packed
• 2 large eggs
• 1 teaspoon vanilla extract
• 3 ripe bananas, mashed
• 1/2 cup sour cream
• 1/2 cup chopped walnuts (optional)