Grilled Lamb, Potato, Bean and Mushroom Salad

1 / 2 cup fresh lemon juice

6 ozs anchovies ( drained oil reserved, chopped )

1 1 / 3 cups oil

1 1 / 2 cups fresh basil ( packed chopped )

1 cup shallots ( chopped )

5 1 / 2 lbs leg of lamb ( fat trimmed boned and butterflied about 3 1 2 pounds boned )

3 lbs red-skinned potato ( potatoes cut into 3 4 inch pieces )

2 lbs wax beans ( yellow, trimmed )

1 lb sliced mushrooms

1 leaf spinach

1 sprig fresh basil