Drain plums good, reserve syrup and chop plums.

Preheat the oven to 400 F. In a large mixing bowlful, beat the butter
until creamy and lightness, then gradually add the sugars, beating until
creamy and smoothen. Beat in the egg, then the vanilla. Sift all dry
ingredients unitedly; stir into the butter assortment, alternating with
1/2 cup of the reserved syrup, beginning and ending with dry
ingredients. Stir in the plums. Pour the batter into a lubricated 9" x
13" baking pan. Bake for 25 to 30 proceedings, or until a toothpick tests
neat. Turn the cake out of the pan and cool on a wire torture. Dust
with confectioners' sugar.