Tunisian Prawns with Kerkennaise Sauce

Ingredients

1. 1 1/4 pounds tomatoes, halved crosswise
2. 1/2 cup chopped scallions (4 large)
3. 1 serrano chile, minced
4. 3/4 teaspoon ground coriander
5. 1/4 teaspoon ground caraway seeds
6. 1/4 cup chopped flat-leaf parsley
7. Pinch of sugar
8. 1 tablespoon white wine vinegar
9. 1 small garlic clove, minced
10. Salt
11. 1/4 cup plus 2 tablespoons extra-virgin olive oil
12. 1 3/4 pounds jumbo shrimp, shelled and deveined
13. Freshly ground pepper
14. 2 teaspoons drained capers

1. Grate the cut sides of the tomatoes against the large holes of a box grater set in a shallow bowl. Discard the skins. Add the scallions, chile, coriander, caraway, parsley, sugar and vinegar to the grated tomatoes. Using the flat side of a chef's knife, mash the garlic to a paste with 1/4 teaspoon of salt. Stir the paste and 3 tablespoons of the olive oil into the sauce and season with salt. Let the Kerkennaise sauce stand at room temperature for 1 hour.
2. Light a grill. In a medium bowl, toss the shrimp with the remaining 3 tablespoons of olive oil and season with salt and pepper. Grill the shrimp over a moderately hot fire until just cooked through, about 8 minutes. Transfer the shrimp to plates and sprinkle with the capers. Serve with the Kerkennaise sauce.