Preheat oven to 375°. In an ungreased 13x9-in. baking dish, combine rhubarb and sugar; toss to combine. Bake, covered, 30-40 minutes or until tender, stirring occasionally. Cool slightly.
Place rhubarb mixture in a blender; cover and process until pureed. Transfer to a bowl; refrigerate, covered, until cold.
Stir lemon juice into rhubarb. In a small bowl, beat cream until stiff peaks form; fold into rhubarb mixture. Transfer to a shallow 1-qt. freezer container. Freeze 1 hour, stirring every 15 minutes. Freeze, covered, overnight or until firm.
Nutrition Facts
1/2 cup: 489 calories, 18g fat (11g saturated fat), 65mg cholesterol, 22mg sodium, 85g carbohydrate (81g sugars, 1g fiber), 2g protein.