Heat oil in a large skillet over medium heat. Add onion and cook for about 3 minutes or until just beginning to soften.
Add bell pepper, tomatoes, preserved lemon and couscous and cook, stirring often, for 3-4 minutes, or until onion is translucent and couscous is beginning to look toasted.
Add vermouth and chicken stock and bring to a boil. Stir, then reduce heat to medium low and simmer 8-10 minutes, covered, until couscous is nearly tender.
Stir in spinach and cook about 2 minutes longer, until spinach is wilted and couscous is fully cooked. Stir in parsley and serve.