DIRECTIONS
Heat the oil over medium heat in a large saute pan.
Add the onions, sugar, cinnamon, red pepper flakes, salt and pepper.
Cook, stirring occasionally, until the onions are golden brown and caramelized, about 30 minutes.
Stir in a few TBSP. of water and the vinegar.
Taste and season with salt and pepper.
Stir in the mint and chopped parsley just before serving.
Heat grill to high.
Brush tuna on both sides with the oil; sprinkle with salt and pepper. Grill the tuna until golden brown and slightly charred on both sides and cooked to medium rare doneness, about 2 minutes per side.
Plate the sliced tuna on a platter and spoon the onion mixture down the center.
Keep at room temperature 15 minutes before serving.
Serves 4.