1. Preheat oven to 375°F.

2. Place halved plums in an 8-inch baking dish.

3. In a small bowl, whisk together the cream, sugar, and cinnamon until combined.

4. Pour the cream mixture over the plums and dot with butter.

5. Bake in preheated oven for 30 minutes, or until plums are tender.

6. Serve warm with a dollop of whipped cream, if desired.