Peel pears, leaving stems intact. Cut small slice off the bottom of each pear so it will stand upright. Arrange pears on their sides in saucepan.
Cover and simmer until pears are tender but still hold their shape, turning once, about 15 minutes per side. Using a slotted spoon, transfer pears to upright position in glass bakingdish.
Boil cooking liquid until reduced to approximately 1/2 cup, about 9 minutes. Watch carefully to make sure liquid is not reduced too far. Pour into small bowl, cover and chill sauce and pears separately until cold, at least 2 hours or up to one day.*
Beatcream in large bowl until soft peaks form. Add Cognac** and sugar and beat until stiff peaks form.