Hearty Stovetop Spring Time Beef Stew

Name: Hearty Stovetop Spring Time Beef Stew
Ingredients: 2 tablespoons vegetable oil; 1 tablespoons olive oil; 1 ½ pound sirloin (trimmed lightly and cubed); 1 onion (chopped); 3 carrots (chopped); 3 stalks celery (chopped); 3 cloves garlic (sliced); ⅓ cup sherry; 2 cups beef stock; 1 ½ cups chicken stock; 1 tablespoon fish sauce; 1 bay leaf; 3 sprigs fresh thyme (tied together with twine); 1 teaspoon rosemary (dried); 4 yukon gold potatoes (chopped); ½ cup green peas (frozen); 1 teaspoon salt (divided, more to taste); ½ teaspoon pepper (and more to taste); parsley (optional)