Heat oven to 350* F. Grease a 9-inch springform pan.

In a large bowl, cream butter and sugar until light and fluffy. Add vanilla and egg. beat well.

Lightly spoon flour into measureing cup and level off. Combine flour, baking powder and salt. Gradually add to butter mixture and mix well.

Spread dough over bottom and 1-inchup the sides of pan. Arrange sliced plums over dough. Sprinkle with sugar and cinnamon