Boil potatoes until tender, about 15 minutes. Drain well, then return to hot pan and mash. Add milk, in small amounts, and stir with a wooden spoon to incorporate. Season with pepper to taste.
Meanwhile, place textured vegetable protein in a bowl and stir in 2/3 cup boiling water. Let stand for five minutes or until hydrated.
Heat oil in a medium non-stick saucepan over medium heat. Add garlic and sauté for 1-2 minutes. Add tomato paste, carrot and tomatoes. Cook, stirring occasionally, until thickened. Stir in textured vegetable protein and rosemary and season with pepper to taste.
Transfer mince mixture to a 2l ovenproof baking dish, top with mashed potato and sprinkle with cheese. Bake for 25 minutes or until golden on top. Serve with leafy mix and slices of crusty sourdough.