Pumpkin Polenta Cake

INGREDIENTS

• 2 cups canned pumpkin puree
• 2 tablespoons butter, room temperature
• 2 eggs, lightly beaten
• 4 egg whites, lightly beaten
• 1/2 cup brown sugar
• 1/2 teaspoon baking soda
• 1 teaspoon salt
• 2 teaspoons ground cinnamon
• 1 teaspoon ground nutmeg
• 1 teaspoon ground cloves
• 1 cup low-fat plain yogurt
• 2 cups polenta or yellow cornmeal