Sprinkle gelatin over Kahlúa in a small bowl; let stand 5 minutes to soften gelatin. Add hot coffee, sugar, and salt; stir until gelatin dissolves (about 2 minutes).
Pour into 6 or 8 lightly greased 4" (1/2 cup) brioche molds; cover and chill overnight.
Use fingers to gently pull jelly away from edges of each mold; unmold onto dessert plates. Dollop with whipped cream; sprinkle with chocolate shavings.
Unmolding Tip: If jelly does not unmold easily, very quickly dip bottom of each mold into hot water to loosen; unmold onto dessert plates.