Rinse and drain the endive; wrap in towels, enclose in a plastic food bag, and chill.
Meanwhile, immerse morels in 2 cups hot water. Let stand until cool enough to handle, 10 to 15 minutes. Holding morels in water, squeeze gently to massage grit free. Lift morels from water and squeeze dry. Carefully pour soaking liquid into another container; discard gritty residue.
Immerse morels in a generous amount of cool water and massage gently again. Lift from water and squeeze dry; discard cool water.
In a 10- to 12-inch frying pan, combine shallots, tarragon, vinegar, and reserved morel soaking liquid. Boil over high heat, stirring, until liquid evaporates, about 12 minutes. Add morels and 1/4 cup cream. Boil, stirring often, until cream evaporates and vegetables begin to brown, about 1 minute.
Add remaining cream, beef broth, wine, and brandy and boil until liquid is reduced to about 3/4 cup, 4 to 5 minutes.
Reserve a few endive leaves to garnish each plate; finely sliver remaining endive lengthwise. Arrange endive leaves and slivers on salad plates.
Bring morel dressing to a boil and ladle over endive. Add salt to taste.