Before starting, preheat the broiler to high. Wash and dry all produce. Peel, then cut potatoes into 1/2-inch pieces. Add potatoes, 2 tsp salt and enough water to cover (by approx. 1 inch) to a large pot (use same for 4 ppl). Cover and bring to a boil over high heat. Once boiling, reduce heat to medium. Simmer uncovered until fork-tender, 10-12 min.

While potatoes cook, peel, then mince or grate garlic. Strip 1 tbsp thyme leaves from stems (dbl for 4 ppl). Heat a large non-stick pan over medium-high heat. When hot, add 1/2 tbsp oil (dbl for 4 ppl), then mirepoix, thyme and garlic. Cook, stirring occasionally, until veggies start to soften, 3-4 min. Season with salt and pepper.

Add lamb to the pan with veggies. Cook, breaking up lamb into smaller pieces, until no pink remains, 4-5 min.** Add peas, half the tomato sauce base (use all for 4 ppl), soy sauce and 1/2 cup water (dbl for 4 ppl) to the pan. Cook, stirring occasionally, until sauce thickens slightly, 5-6 min. Season with salt and pepper. Remove the pan from heat and transfer lamb mixture to an 8x8-inch baking dish (9x13-inch for 4 ppl).

Drain and return potatoes to the same pot, off heat. Mash 2 tbsp butter (dbl for 4 ppl) into potatoes until creamy. Stir in sour cream. Season with salt and pepper. Top lamb mixture with mashed potatoes. Smooth mashed potatoes over top, covering lamb mixture.

Sprinkle Parmesan over assembled shepherd's pie. Broil in the middle of the oven until topping is golden-brown, 2-3 min. (TIP: Keep an eye on it so it doesn't burn!)

Let shepherd's pie cool slightly, 4-5 min. Divide shepherd's pie between plates.