Arrange a rack in the lower third of the oven. Preheat the oven to 350.
Cream the butter and the 3/4 c. sugar. Add the flour, baking powder, eggs, and salt and beat to mix well. Spoon the batter into an ungreased 9 or 10-inch springform pan. Cover the top with the plums, skin sides down. Mix the cinnamon with the 2 T. sugar and sprinkle over the top.
Bake for 40 to 50 minutes, until the cake tester inserted in the center comes out clean. Remove from the oven and let cool; refrigerate or freeze if desired.
To serve, let the torte return to room temperature and reheat at 300 until warm. if desired. Serve plain or with vanilla ice cream.
Serves 8.
NOTE: "Because of reader demand, this recipe has been published in one form or another in The New York Times almost every year since I went to work there in 1981. Lois (Levine) brought this recipe, originally called Fruit Torte, to Elegant but Easy, and its appeal comes from its lovely old-fashioned flavor and its speed of preparation..." Kirsten A> Conover