-into small pieces * or crystallized ginger, each about 3/4 inch in diameter Preheat oven to 375'. Rinse the rhubarb and pat dry. Trim off all the leaves and roots (they contain oxalic acid, which is toxic). Cut stalks into 1 inch pieces and place in a large bowl. Coarsely chop the ginger and mix with the rhubarb. Sift together the sugar and the cornstarch; toss with the rhubarb. Transfer to a 2 1/2-quart shallow baking dish. Set aside. The topping: Combine the flour, sugar and salt in a food processor; pulse a few times to mix. Add the chilled butter and process until the mixture turns crumbly, just a few seconds. Sprinkle the crumb topping over the rhubarb. Bake until the topping turns golden brown and the rhubarb is bubbling. Serve warm with scoops of vanilla ice cream. PER SERVING (with 1/2 cup ice cream): 425 calories, 4 g protein, 62 g carbohydrate, 19 g fat (11 g saturated), 61 mg cholesterol, 86 mg sodium, 2 g fiber. From an article by Joyce Jue in the San Francisco Chronicle, 9/15/93.