Lemon Herb Barbecued Shrimp

1 1/2 cups catsup
1/2 cup white vinegar
1/4 lemon, seeded and finely minced (rind too!)
1 tablespoon Gravy Master
1 teaspoon sugar
1 teaspoon ground coriander
1/2 teaspoon ground cumin seed
1/4 teaspoon ground ginger
1/8 teaspoon paprika
Cayenne pepper to taste
2 pounds large shrimp (20 to 32), shelled and deveined

Directions:

1. In a small saucepan, combine catsup, vinegar, lemon, Gravy Master, sugar, coriander, cumin, ginger, paprika and Cayenne pepper.
   
2. Simmer 15 minutes, stirring frequently.
   
3. Thread shrimp on skewers.
   
4. Grill 4 to 6 inches from hot glowing coals for 3 to 5 minutes, turning and brushing frequently with lemon mixture. Do not overcook.
   
5. Serve immediately. Makes 6 to 8 servings.