How to prepare:
Remove the central bone from the lamb chops.
Trim off fat and neaten into nice "rump" or rounded shapes.
Place in a bowl or plastic bag with half of the olive oil and the leaves from
the thyme sprig.
Set aside to marinate in the fridge.
Cook the lentils in boiling salted water for about 15 minutes.
Drain and season with salt and pepper.
Cut the carrot, celeriac, and leek into 1/2-inch squares (we call this a brunoise).
Heat the remaining oil in a saucepan and saute the vegetables until lightly browned,
5 to 7 minutes.
Add the lentils and half the parsley, then bind with 2 tablespoons of the vinaigrette.
Set aside.
For the gratin potatoes, preheat the oven to 400 F (200 C).
Peel the potatoes and slice thinly (use a mandoline or the slicing blade of a food
processor).
Bring the milk and cream to a boil with some sea salt, the garlic, and herbs, and
simmer for a couple of minutes.
Add the sliced potatoes and simmer for about 5 minutes until just tender.
Drain in a colander set over a bowl to catch the creamy milk.
Mix the potatoes gently with two-thirds of the gruyere cheese.
Layer neatly into four medium ramekins or gratin dishes, seasoning in between the
layers with salt and pepper.
Spoon a little of the saved creamy milk on top of each ramekin and sprinkle with the
last of the cheese.
Place the ramekins on a baking sheet and bake for 8 to 10 minutes until the cheese
just turns a golden brown.
Meanwhile, heat a heavy-bottomed nonstick frying pan until really hot.
Remove the lamb steaks from the bowl or plastic bag, wiping off any thyme leaves,
and brown for 3 to 5 minutes on each side, seasoning lightly as they cook.
The lamb should be served lightly pink -- medium rare.
Reheat the lentils and spoon onto the center of four plates.
Place the lamb steaks on top (slice them first, if you like).
Deglaze the frying pan with the last of the vinaigrette, stirring for a minute, then
spoon these juices over the lamb.
Sprinkle with the remaining parsley.
Serve the gratin potatoes, still in their individual dishes, on the same plate.