Brochettes a la Camerounaise

Ingredients
Marinade:
 * A few pounds of beef, cut into bite-sized pieces
 * onion, sweet green pepper, tomatoes (optional); cut into bite-sized pieces
 * oil
 * vinegar (or cider vinegar)
 * tomato, chopped
 * onion, finely chopped
 * garlic, minced
 * fresh ginger, minced
 * cayenne pepper or red pepper
 * salt

Directions

 * 1) Use a mortar and pestle to grind together all of the marinade ingredients.
 * 2) In a glass bowl mix the meat and marinade, thoroughly covering the meat.
 * 3) Allow the meat to marinate for several hours if possible.
 * 4) Place the meat (and vegetables, if desired) on skewers.
 * 5) Cook the skewered meat under the oven broiler.
 * 6) Baste with the remaining marinade, making sure the marinade is fully cooked after the last basting.