- In a saucepan, bring the liqueur, citrus zest and juice and sugar to a boil. Reduce until mixture is slightly syrupy.
- Preheat the grill, setting the burners to high. Oil the grate.
- In a bowl, toss the fish in half the citrus sauce. Insert three cubes of monkfish on each skewer. Season with salt and pepper.
- Grill the skewers for 1 to 2 minutes per side.
- Place the skewers on a serving platter and brush with the remaining citrus sauce. Sprinkle with cilantro.
To prepare the monkfish, completely remove the reddish membrane.