Prepare the vinaigrette. Drain the artichokes and discard the marinade or set it aside for another use. Cover the drained artichokes with the vinaigrette. Set aside until ready to serve.

Place the onions and butter in a heavy saucepan over medium-low heat and sauté for 2 to 3 minutes. Combine the sugar, vinegar, salt, and pepper, add to the onions, and cook for 2 to 3 minutes more or until lightly golden. Add the coffee syrup, mix, and remove from the heat. Allow the onions to cool to room temperature.

Drain the vinaigrette from the artichokes into a small pitcher, and cut the artichokes into quarters. Arrange the lettuce on a platter or individual serving plates.

Pour the vinaigrette over the lettuce; arrange the onions and artichokes on top. Serve.