In a sauté pan, heat the olive oil. When the oil is hot, sauté the onions for about 10-12 minutes or until golden. Season with salt, pepper, and cayenne. Add the sugar and cook for 2 minutes, stirring constantly. Add the vinegar and parsley and cook for 1 minute. Remove from the heat and cool. On a platter, serve the slice ballotine with the croutons, mustard, cornichons and onion marmalade.
Yields: 1 1/2 cups