Dissolve the yeast and 1 tablespoon sugar in warm water in a small bowl, and let stand 5 minutes. Lightly spoon the flour into dry measuring cups, and level with a knife. Place flour, 3 tablespoons sugar, and salt in a food processor, and pulse 3 times or until blended. With processor on, slowly add the yeast mixture, margarine, and egg through food chute, and process until the dough forms a ball. Process the mixture 1 additional minute. Turn dough out onto a lightly floured surface, and knead lightly 4 to 5 times. Place dough in a large bowl coated with cooking spray, turning to coat top. Cover and let rise in a warm place (85°), free from drafts, 1 hour or until dough is doubled in bulk.
Preheat oven to 425°.
Punch dough down. Pat dough into a 12-inch pizza pan coated with cooking spray, and place pan on a large foil-lined baking sheet. Arrange the plum slices in concentric circles over dough, and gently press plum slices into dough. Sprinkle 1/3 cup sugar over plum slices, and top with raspberries. Bake kuchen at 425° for 20 minutes or until puffy and edges are well-browned. Remove from oven, and drizzle with melted jam. Cool on a wire rack.