Halve and core pears. Place, cut-side up, in baking dish. Sprinkle with lemon juice. In small saucepan, mix together cornstarch and 1 juice can of water. Heat to boiling, reduce heat and simmer, stirring constantly, until thickened and clear. Pour over pears. Bake in 350F oven for 30 minutes or until pears are tender, basting occasionally with sauce. Makes 6 servings.