Hachis Parmentier
Lentilles du Puy simmered with a classic mirepoix until rich and deeply savoury, topped with buttery mashed potato and golden Gruyère. Earthy, peppery lentils underneath, soft buttery mash on top, and that gratiné crust holding it all together!
Ingredients
For the lentil filling
- 300 gr lentils lentilles du Puy AOP if you can find them
- 1 onion
- 2 carrots
- 2 sticks celery
- 2 cloves garlic
- 2 tbsp olive oil
- 2 tbsp tomato concentrate
- 500 ml vegetable stock
- 3 sprigs thyme
- 2 bay leaf
- 1 tsp red wine vinegar
- salt and black pepper
For the mashed potato topping
- 900 gr floury potatoes
- 60 gr unsalted butter
- 100 ml whole milk
- 2 tbsp crème fraîche
- 1 pinch nutmeg
- salt and black pepper
To finish
- 80 gr Gruyère cheese
Equipment
- 1 braisière shallow dutch oven
- 1 saucepan
- potato ricer or masher
Instructions
1. Cook the lentils
- Rinse the lentils (no need to soak). Put them in a saucepan, cover with cold water, bring to the boil and cook for about 20 minutes, until just tender with some bite. Don't salt the water, it toughens the skins. Drain and set aside.
2. Build the filling
- Heat the olive oil in the braisier over medium heat. Add the onion, carrot and celery (mirepoix) and cook gently for 10 minutes until softened. Add the garlic for 2 minutes, then the tomato purée and cook out for 2 minutes. Add the stock, thyme and bay, season, then stir in the lentils. Simmer 15 to 20 minutes until the sauce clings to the lentils. Stir in the vinegar, adjust seasoning, remove the herbs.
3. Make the mash
- Meanwhile, boil the potatoes in salted water for about 20 minutes until tender. Drain and steam-dry for a couple of minutes. Rice or mash smooth. Beat in the butter, then the warm milk and crème fraîche. Season with salt, pepper and nutmeg.
4. Top and bake
- Heat the oven to 200°C (180°C fan). Spread the mash over the lentil filling, right to the edges. Rough the surface with a fork and scatter over the Gruyère. Bake for 25 minutes until golden and bubbling, finishing under the grill for 3 to 4 minutes for a properly golden top.
5. Rest and serve
- Rest 5 minutes (the filling is very hot). Serve from the dish, with a green salad and a sharp mustard vinaigrette.
Notes
- Lentils du Puy specifically is what makes this work. They hold their shape through cooking and have a mineral, earthy flavour that generic green lentils simply can't match. Look for the AOP label if you can find it.
- Don't rush the mirepoix. Ten minutes of gentle cooking builds the flavour base the whole dish rests on. If the vegetables go in barely softened, the filling will taste flat.
- The tomato concentrate is there as background, not as a feature. Two tablespoons is enough to add depth and a little colour without announcing itself. This dish is about the lentils.
- A wide, shallow braisier works better here than a deep casserole. You want a good ratio of mash to filling in each spoonful, and a deeper dish throws that off. The wider the better for the gratin on top too.
- Make ahead: build the whole thing up to the baking stage, leave to cool, and refrigerate for up to 24 hours. Take it out of the fridge 30 minutes before baking and add 10 minutes to the oven time.
- Leftovers keep well in the fridge for 2–3 days and reheat brilliantly in the oven at 180°C for 20 minutes, covered with foil.
- Comté works just as well as Gruyère on top, and arguably better, it has a slightly nuttier, more complex flavour that's worth trying if you can find it.