Apple Coffee Cake With Brown Sugar Sauce

Ingredients

• 2 apples - peeled, cored and chopped
• 2 1/2 cups all-purpose flour
• 1 1/2 cups packed brown sugar
• 3/4 cup butter, softened
• 1 cup chopped walnuts, toasted
• 1 teaspoon baking soda
• 1 teaspoon ground cinnamon
• 1/2 teaspoon salt
• 1 egg
• 3/4 cup sour cream
• 1 teaspoon vanilla extract