I just made a fish pie, based on a Jamie Oliver recipe, that was great. Very easy to prepare, despite the longish looking ingredient list, and it really was yummy. My husband balked at the sound of FISH PIE but LOVED it once he dug in. Good luck!
Fantastic Fish Pie
6 large potatoes, peeled and diced into 1-inch squares
2 free-range eggs
2 large handfuls fresh spinach, trimmed and washed
1 onion, finely chopped
1 carrot, halved and finely chopped
Extra-virgin olive oil
1 cup heavy cream
2 good handfuls grated mature Cheddar or Parmesan
1 lemon, juiced
1 heaped teaspoon English mustard
1 large handful flat-leaf parsley, finely chopped
1 pound haddock or fresh cod fillet, skin removed, pin-boned and sliced into strips
Salt and freshly ground black pepper
Preheat the oven to 450 degrees F.
Put the potatoes into salted boiling water and bring back to a boil for 2 minutes. Carefully add the eggs to the pan and cook for a further 8 minutes until hard boiled, by which time the potatoes should also be cooked. At the same time, steam the spinach in a colander above the pan. This will only take a minute. When the spinach is done, remove from the colander and gently squeeze any excess moisture away. Then drain the potatoes in the colander. Remove the eggs, cool under cold water, then peel and quarter them. Set aside.
In a separate pan slowly fry the onion and carrot in a little olive oil for about 5 minutes, then add the heavy cream, and bring just to a boil. Remove from the heat and add the cheese, lemon juice, mustard, and parsley.
Put the spinach, fish and eggs into an appropriately sized earthenware dish (I used a glass pie dish) and mix together, pouring over the creamy vegetable sauce. The cooked potatoes should be drained and mashed, add a bit of olive oil, salt, pepper, and a touch of nutmeg, if you like. Spread on top of the fish. Don't bother piping it to make it look pretty, it's a homely hearty thing. Place in the oven for about 25 to 30 minutes until the potatoes are golden.
This will not be popular but I don't see why you should be obliged to change your menu to accomodate this person. S/he knew when s/he accepted your invitation that you don't follow his fish only diet plan. To expect you to change what you had planned to make is rude. Accept and eat what is offered or say you would love to join them for dessert and go eat your fish somewhere else. I for one find fish in the part of the country where I live repugnant, I have pushed it around on my plate as any number of dinners. I have never expected a host to change a menu to accomodate me. It reminds me of that article in Food and Wine last year about the poor person who invited a bunch of friends for Thanksgiving and all of the guests refused to eat what she had prepared. The meal was a disaster because she prepared a traditional meal and each guest wanted to impose his/her dietary plans on the hostess. None of those people would have been invited back to my house.
If Candy hadn't posted first with this sentiment then I would have. I say go ahead and serve your x-number servings of chicken pot pie plus 1 serving of fish, perhaps oven-baked. Since the guest list changed "suddenly" you shouldn't be expected to turn all your dinner plans upside down at the last minute as well. The dinner parties I've given have all involved long musing and preparation beforehand and to have to change in the 11th hour is often impossible. As long as there is something for your finicky guest to eat, it doesn't have to match everyone else's menu.
Okay, I'll bite (so to speak).
The OP said:
"I am having a dinner party tomorrow and suddenly a piscatarian is coming- chicken pot pie out."
Nothing in this suggests that the OP doesn't want the person there or that the OP doesn't want to accommodate or even that the guest "expects" the OP to change the menu. Why are you imputing so much blame on the guest? Also, I think you misunderstand pescetarianism: it's not about insisting on fish at every meal; it's basically vegetarianism with the additional option of eating fish--often, I should add, for the sake of comity.
I would make the base for the chicken pot pie, though using veg. stock instead of broth--make the roux, thicken, remove a single serving, add vegs then make separate potpie in a small oven proof dish. Continue to make the pot pie and add chicken, bake all at once. Your guest will get the warmth of the potpie, with the "look" of the regular meal, feel included and get a veggie meal. Good luck!
You could always try throwing in chunks of Salmon or even oysters (love 'em both raw and cooked) in there instead of chicken... although there is always the chance that the seafood will be overcooked.
Btw, what's the reason for this person's piscatarianism, if you don't mind my asking?