Cut a large navel orange in half crosswise and cut a thin slice off the bottom of each half so it will sit steady on a foil covered baking sheet. Then run a knife around each half to loosen the orange from the peel. Do not remove the peel, however. Stir together 2 tsp melted butter and 1/2 tsp chopped fresh mint. If desired, you may add 1 tbsp of orange liqueur. Spoon the mixture evenly over the cut sides of the orange halves. Place the orange halves, cut side up, on the foil lined baking sheet.
Broil five inches from heat for five to eight minutes or until thoroughly heated.