Pettigrew, 36, recently opened a "gastro bar" called Stella Maris (Latin for "star of the sea") with his fellow Irish-American partner Keith Doyle in New York.
He describes the food at the restaurant, divided into a separate cafe, dining room and bar, as "uncomplicated modern bistro fare."
Besides an extensive raw seafood bar and classic European dishes from France, Spain and Italy, Pettigrew includes a few Irish favourites as well, cockles and mussels, crubeens (Gaelic for pigs' feet) and pea soup which he calls a "wink at Dublin."
Q: How would you define Irish cuisine?
A: "We've got a bad rap. Let's just say there is no Irish cuisine. There are a couple dishes, there's a working man's dish, we're going to do it here. It's basically boiled sausages and Irish bacon and potatoes and a few vegetables. It's called coddle. You have it with a pint of Guinness and some brown bread. The joke is corned beef and cabbage; you don't eat corned beef in Ireland."
Q: Do you have a culinary mentor?
A: "Venison and chocolate became popular a couple years ago. The guy I was working with 15 years ago in Ireland in a yacht club was doing all this stuff. His name is Cormac Healy. He's the executive chef of the National Yacht Club in Dunleary. He was just one of those unsung heroes, the background guy, a big family man. All the guys I've worked with haven't got loads of Michelin stars but they could cook you under the table."
Q: What inspires you to create new dishes on a daily basis?
A: "What inspires me is coming into fall now, now is my time. This is what I love to do. I love to slow roast and braise meat and caramelise and roast vegetables, and pull out the natural sugars and the deep complex flavours that come with those techniques... Autumn food reminds me of Irish food. The stews, the casseroles, the roasts. Sitting around the table with your family on a Sunday."
Q: Are you experimenting with any new ingredients?
A: "I just bought a small tin of Argan oil. It's like 55 bucks (dollars) for less than a quart. I'm going to do it with a Moroccan-spiced pork and tender lamb shank with a spicy dried-fruit couscous. The Berbers have been using it for thousands of years. It's made from olive trees indigenous to Morocco. The stuff is just phenomenal.
Q: What is your favourite food to eat?
A: "I just love roast chicken. It's very simple. I fill the cavity with loads of herbs and put porcini mushrooms and truffles under the skin. I serve it with little Tokyo turnips, multicoloured carrots, snap peas, English peas and Parisian potatoes."