Keema shepherd's pie with mashed aloo masala

Grate the onion, carrots, garlic and ginger on a box grater; the aromatics melt away as they cook.

Separate half the garlic and ginger, slice the green chilies and separate half of those, for the aloo masala.

Grate the gruyere; half goes into the potatoes and half over the top.

Peel and dice the potatoes, then wash them to remove excess starch that would make the mash gummy.

Squish the ground lamb down in a cast iron over medium-high heat and cook, stirring and scraping, until well browned, breaking it into small pieces.

Turn the heat to low, add the grated onion, carrot, garlic, ginger and green chili and cook about five minutes until softened.

Add the cloves, bay leaf, crushed mustard and cumin seed, hot chili powder, turmeric and garam masala and cook about 30 seconds.

Add the diced tomatoes, Worcestershire sauce, mushroom bouillon and tomato paste and simmer 5 to 10 minutes until reduced and thickened.

Stir in the frozen peas, turn off the heat and adjust with salt.

Boil the diced potatoes in salted water until a spoon pierces them easily, about 10 minutes.

Drain. In the empty pot heat a drizzle of oil and fry the black mustard and cumin seed until the mustard seeds pop.

Add the reserved green chili, garlic and ginger with a sprinkle of turmeric, saute about a minute and spoon into a bowl.

Rice the potatoes - a shepherd's pie wants a homogenous topping rather than the rough half-mash of a traditional aloo masala.

Stir the spice and aromatic oil mixture into the riced potatoes, then the butter and milk.

Fold in half the grated gruyere, load the potato into a freezer bag and pipe it over the smoothed lamb filling in the cast iron.

Smooth flat, then roughen the surface with a fork to make nooks that brown, and sprinkle over the remaining gruyere.

Bake in a preheated 425 degree Fahrenheit oven about 20 minutes until lightly browned and crisped.

Rest 20 minutes so it firms up for serving.