Viennese Plum Cake - Master recipes

Ingredients

• 1/2 cup butter, softened -
• 1/2 cup plus 1 tablespoon sugar, divided -
• 2 eggs -
• 1 teaspoon vanilla extract -
• 1 cup all-purpose flour -
• 1 teaspoon baking powder -
• 1/4 teaspoon salt -
• 3 cups sliced fresh or frozen plums (about 1-3/4 pounds fresh) -
• 1/4 teaspoon ground cinnamon -
• Topping: -
• 1/2 cup all-purpose flour -
• 1/4 cup sugar -
• 1/4 cup cold butter, cubed -
• 3 tablespoons chopped walnuts, optional -