Heat oven to 375°. Grease bottom and sides of square baking dish, 8x8x2 inches, with shortening. Mix granulated sugar and cornstarch in 3-quart saucepan. Add berries and lemon juice; toss until evenly coated. Heat to boiling over medium-low heat. Boil 3 to 4 minutes, stirring frequently, until thickened. Spoon berry mixture into baking dish.
Mix brown sugar, flour, oats, cinnamon and salt in large bowl. Cut in butter, using pastry blender or crisscrossing 2 knives, until mixture looks like coarse crumbs; sprinkle over berries.
Bake about 30 minutes or until topping is golden brown. Cool at least 20 minutes. Serve warm with whipping cream.