Shepherd’s Pie also known as Cottage Pie came about when potatoes were being introduced as an affordable crop. Then, it was made with any leftover meats, typically lamb or mutton, mixed with vegetables and covered with mashed potatoes.
Peel potatoes and cut into 1/2-inch dice. Bring to boil, simmer until tender 10-15 minutes. Warm butter in half-and-half for 35 seconds in microwave. Drain potatoes and return to saucepan. Add half-and-half, butter, salt and pepper. Mash until smooth. Stir in the yolk until well combined.
Saute onions and carrots in canola oil approximately 3 minutes. Add garlic, lamb, salt and pepper. Cook until browned. Stir in flour continuing to cook for another minute. Add tomato paste, chicken broth, Worcestershire, rosemary, thyme and stir to combine. Bring to a boil, reduce heat to low, cover and simmer 10-12 minutes or until the sauce is thickened slightly.
Add corn and peas to lamb mixture. Spread evenly into an 11 x 7-inch glass baking dish. Top with mashed potatoes, smooth with a rubber spatula making sure to seal the edges. Bake for 25 minutes or just until the potatoes begin to brown.
*Reduce salt if using a regular fine grind table salt.