Old Fashioned Plum Cake

Ingredients

• 2 cups unsifted flour
• 1 teaspoon baking powder
• 1/2 teaspoon baking soda
• 1/4 teaspoon salt
• 1/2 cup butter or 1/2 cup margarine, softened
• 1 cup sugar
• 3 eggs
• 1 teaspoon vanilla extract
• 3/4 cup sour cream
• CRUMB TOPPING
• 1/4 cup sugar
• 2 tablespoons flour
• 1 tablespoon butter or 1 tablespoon margarine, softened
• 1/2 teaspoon ground cinnamon
• 9 fresh Italian plums or 9 canned purple plums
• 2 tablespoons plum jam or 2 tablespoons red currant jelly, melted