Gluten-Free Shepherd's Pie

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.