Butter bottom and sides of 10 inch springform pan.
Position baking sheet on rack in center of oven.
Cook puree in small nonaluminum saucepan over medium-high heat until reduced to 1/4 cup.
Combine...
Combine oil, butter and onion in heavy large saucepan.
Cover and cook over low heat 1 hour.
Stir in 1 teaspoon sugar with salt.
Cover and cook another hour, stirring to prevent sticking.
Add plums,...