How to Make It
In a nonreactive medium saucepan, sprinkle the gelatin over 1/2 cup of cold water. Let stand for 5 minutes to soften. Add the sugar and cook over moderately low heat, stirring constantly, until the gelatin is completely dissolved; don't let it boil. Stir in the orange juice and liqueur. Pour the mixture into 4 small bowls, ramekins or wine glasses. Cover with plastic wrap and chill until set, at least 4 hours or overnight.
If using bowls or ramekins, dip the bottoms in warm water for 30 seconds. Run a small knife around the sides of each mold and invert onto small plates. Garnish with orange slices and mint and serve.