A high number of Irish (compared to other nationalities) seem to be plagued by gluten intolerance/Celiac disease. Apparently, the Irish have conspiracy theories involving the English and Celiac. The leading theory claims that it's due to the fact that the English shipped all the wheat out of Ireland at one point, so the Irish people never got used to eating it.
For whatever reason, eight years ago, almost to the day, I was diagnosed with Celiac disease. And as an American-Irish girl, it was my duty to make a shepherd's pie for St. Patrick's Day, so I had for come up with a couple of easy substitutions. I found it to be daunting.
The year before, I found myself eating the most incredible shepherd’s pie, better than my mother’s, at a pub in the Boston area. (In my eyes, my mother, bless her soul, was the most incredible cook ever.) But back to this newfound shepherd’s pie benchmark that I found at Matt Murphy’s Pub in Brookline, Mass. At first, it looked ordinary with a browned topping of mashed potatoes, but once I dug in, I could see chunks of stew meat and rosemary. This is the version that I had to reproduce.
In my mind, the ultimate shepherd’s pie is a base of tasty lamb stew with lots of rosemary topped with browned creamy mashed potatoes. The only two components that are not gluten-free are the flour and beer. (Easy substitutions as I will get to below.) I suggest drinking a gluten-free beer with it such as Green's dark ale. Brewed in Belgium, it does not quite resemble an Irish Stout beer, but it is close enough.
For the stew:
Season the potato starch well with salt, pepper, and cayenne in a large mixing bowl. Toss the lamb with starch mixture in bowl, until evenly coated. Warm a large, 12-inch skillet and add oil over medium-high heat. Brown the meat in the skillet, until the coating is browned on both sides. Split into 2 batches if needed. (Do not overcrowd or will not brown well.) Remove from heat. Place the seared meat and gluten-free beer into a slow cooker or a large (3-4 quart) heavy sauce pan; put on low heat.
Cook onions in the same skillet as the lamb, adding more oil if needed, over medium heat until transparent; remove and add onions to meat. Add the carrots, mushrooms, tomato paste, bay leaves, and half the rosemary to the lamb and onion mixture and stir until thoroughly mixed on low heat. Cook covered, with occasional stirring, for at least 2 hours. 30 minutes before removing stew from heat, add in the peas, the remaining rosemary, and thyme. Taste for seasoning, adding in more salt and pepper as needed.
For the whipped potatoes:
Boil the potatoes with salt until tender, about 15-20 minutes. Then drain well. Place potatoes into a large mixing bowl and add butter in small pats, while potatoes are still hot. Using a hand mixer, beat the potatoes on low until smooth. Add in any remaining butter, salt, and white pepper to taste. Increase mixer speed to medium speed, and beat until smoother. Slowly add all the milk using a low mixing speed; increase mixing speed to make fluffy. Add more milk if needed to make creamier.
To assemble, turn on broiler. Using an oven-safe casserole dish (individual soufflé dishes or 1 large dish), fill the dish halfway with the stew, smoothing it out to make sure it is evenly distributed. Place potatoes on top and carefully spread out to cover the top of the stew. Sprinkle with chopped parsley. Place under broiler for about 5 minutes, until potatoes are lightly browned.