Shepherd's Pie with Carmelized Onions and Cheddar Smash
From Cooking with Shelburne Farms.
For the Carmelized Onions
1.5 TB Olive Oil
1 lb Onions (about 3 medium), thinly sliced crosswise into rounds
1 tsp kosher salt
For the Potato Smash
1.5 lbs potatoes, scrubbed but not peeled and cut into 2 inch chunks
2 garlic cloves, smashed with the flat of a knife
1/2 tsp kosher salt, plus more to taste
1/4 stick butter, cut into 4 pieces
For the Lamb Filling
1/2 TB olive oil
2 medium carrots, scrubbed trimmed and finely diced (about 1.5 cups)
1 lb ground lamb
3/4 tsp fresh thyme minced
1/2 tsp kosher salt
1 TB flour
1/2 TB tomato paste (or ketchup)
1 cup chicken stock
1/2 cup grated cheddar
Make the carmelized onions (up to one week ahead):
Heat oil in a heavy bottomed skillet over medium hear. Add onions and turn heat down to medium low. Sprinkle onions with salt and cook, stirring frequently to make sure they brown evenly, for 30-40 minutes or until golden brown and soft. Set aside.
Make the smashed potatoes (up to 24 hours ahead):
Place a colander in a pot large enough to accommodate it, fill pot with water to bottom of colander, add potatoes and garlic cloves and sprinkle them with salt. Cover, set over high heat, and bring water to a boil. Reduce heat to active simmer and steam for 25-30 minutes until they break apart easily when poked. Remove colander from pot, pour water from pot, return potatoes and garlic to the pot. Cover with a clean dish towel and let potatoes dry out for about 5 minutes (but do not let them cool before mashing). Add the butter to the pot and use a potato masher to smash the potatoes and garlic until blended, but not smooth. Set aside.
Make the meat filling and finish pie:
In a large skillet set over med-high heat, heat olive oil until hot. Add diced carrots and cook, stirring occasionally, for 5-7 minutes until softened. Add lamb, thyme, and salt and cook, stirring occasionally for 8-10 minutes until the meat is no longer pink. Pour off the fat and discard. Sprinkle flour over the meat and cook for 1 minute, stirring. Then stir in the tomato paste and cook, stirring, for 2 minutes longer. Pour in the stock, along with half of the carmelized onions. Increase the heat to high and simmer until gravy thickens slightly.
Spread lamb into a shallow casserole or baking pan. Spread potatoes on top. Distribute the remaining carmelized onions over the potatoes, and then sprinkle the cheddar in top. Bake until top is golden and crusty, about 20 minutes.