WATERCRESS MUSTARD BUTTER:

1 c. watercress leaves, minced
1/2 c. (1 stick) unsalted butter, room temperature
1 tbsp. minced shallot
1 tbsp. Dijon mustard or to taste
1/4 tsp. salt or to taste
Freshly ground pepper
6 (1 inch thick, 8 oz.) salmons steaks
Salt and freshly ground pepper
Watercress springs

For butter: Thoroughly combine first 6 ingredients in small bowl. Adjust seasoning. Refrigerate one hour, at least. (Can be prepared 1 day ahead.)

Adjust barbecue rack 4 inches from fire. Prepare barbecue grill. Season salmon with salt and pepper. Dot with slightly less than half of watercress butter. Arrange buttered side up on rack. Grill 4 minutes. Turn steaks, dot with remaining butter. Cook until just opaque, about 3 minutes. Transfer to plates. Garnish with watercress springs and serve immediately. Serves 6.