Before starting, preheat the broiler to high. Wash and dry all produce. Add 10 1/2 cups water and 1 tbsp salt to a large pot (use same for 4 ppl). Cover and bring to a boil over high heat. Peel, then cut potato into 1-inch pieces. Peel, then cut half the onion (whole onion for 4 ppl) into 1/4-inch pieces. Peel, then grate carrot.Peel, then mince or grate garlic.

Heat a large non-stick pan over medium-high heat. When hot, add 1/2 tbsp (1 tbsp) oil, then garlic, onions, carrots, peas and beef. Cook, breaking up beef into smaller pieces, until no pink remains, 4-5 min.** Stir in broth concentrate, 1/2 tsp (1 tsp) salt and 1/4 cup (1/2 cup) water. Season with pepper. Bring to a simmer. Once simmering, reduce heat to medium. Cook, stirring often, until filling thickens slightly, 3-5 min.

Meanwhile, add cauliflower and potatoes to the boiling water. Cook, stirring occasionally, until tender, 9-10 min. Drain and return to the same pot, off heat. Roughly mash sour cream and 2 tbsp (4 tbsp) butter into cauliflower and potatoes until slightly creamy. Season with salt and pepper, to taste.

Transfer beef filling to an 8x8-inch baking dish (9x13-inch for 4 ppl). Top with mashed cauliflower and potatoes, then spread into an even layer. Broil in the middle of the oven until mash is golden-brown on top, 5-6 min.

Let cottage pie stand for 5 min before serving.Divide between plates.