Adapted from Joy of Cooking, I'm excited to share a truly Irish recipe that is perfect for St. Patrick's Day. This Shepherd's Pie is filled with ground lamb, but you can sub for ground beef to make it Cottage Pie. This was a hit with the whole family!
Set a pot of water over high heat and cut the potatoes into 1 to 2" sized pieces (keep the peel on). Boil until tender when pierced with a fork, about 16 to 18 minutes. Once done, drain the potatoes and blend (with an electric mixer or potato masher) along with the butter, milk and salt. Set aside.
Meanwhile, preheat the oven to 400 degrees F and start chopping the veggies. Dice the onion, celery and carrot and mince the garlic. Heat the olive oil in a medium sized sauté pan over medium heat and add the veggies and garlic to the pan. Cook until softened but not brown, about 2 to 3 minutes.
Add the ground meat to the pan, breaking it up with a spatula, and cook until the meat is brown all the way through (about 5 minutes). Drain off the excess fat and discard. I find that making a tiny crack with the lid of the pan is the easiest way to pour off fat.
Keeping the heat on medium, sprinkle the meat and veggie mixture with the flour. Once it's absorbed add the broth, rosemary, thyme, salt and pepper to the pan. Cook while stirring occasionally for a few more minutes until the broth thickens.
Pour the meat mixture into the bottom of an 8" or 9" square, round or oval casserole dish. Carefully add the mashed potatoes on top. I find it easiest to add dollops all around the pan before attempting to spread it out. Then the key is to make "peaks" in the potatoes with a rubber spatula so it will brown nicely in the oven (I did this by making indentions with the spatula so the peaks would naturally form around it). Bake until the peaks are golden brown, about 20 to 25 minutes. Serve warm and enjoy!