1/2 cup unsalted butter (soft)
1/2 cup assorted fresh minced herbs (such as chervil, parsley, chives, and tarragon)
4 6 to 8 ounce halibut fillets
1 large russet potato (peeled)
2 pounds fresh English peas (in the pod)
  Fresh chervil sprigs (as optional garnish)
1 yellow onion
1 tablespoon sherry wine vinegar
1 1/2 cups chicken stock or water
1 tablespoon butter
1 fresh sprig of rosemary