Good-Cooking - Orange Pound Cake with Orange-Caramel Sauce

Ingredients

• Vegetable cooking spray
• 1 1/2 cups all-purpose flour
• 1/2 teaspoon salt
• 1/4 teaspoon baking powder
• 1/4 teaspoon baking soda
• 1 large orange
• 1 cup granulated sugar
• 1/2 cup buttermilk or sour milk, at room temperature
• 1/2 teaspoon vanilla extract
• 1/4 cup butter, softened (no substitutes)
• 1 large egg
• 2 large egg whites
• 2 tablespoons water
• 1/4 cup granulated sugar