Chocolate Applesauce Cake

6 tablespoons butter
1 cup granulated sugar
1 cup unsweetened applesauce
1 teaspoon ground cinnamon
1 teaspoon vanilla extract
3 eggs
4 (1 ounce) squares unsweetened baking chocolate, melted
1 1/2 cups all-purpose flour
2 teaspoons baking soda
1 teaspoon baking powder
Pinch salt
1/3 cup buttermilk
3/4 cup semisweet chocolate chips
1/2 cup chopped walnuts
Sifted confectioners