When I got home last night, it was so hot I could feel the heat of the earth through the soles of my shoes. We're in the middle of a canecule, which is what the French call a heatwave on steroids. 

But despite the weather making most food unappealing, you've still got to eat. I made it home too late to be able to buy anything at the locals shops or supermarkets, and so had to look at the garden and chicken coop for inspiration. 

Fortunately, we had both leeks and eggs, which inspired me to cook one of my daughter's favourite lazy-day recipes. This recipe comes from Orangette, one of the best - and best-known - food blogs on the internet. My daughter swears by it, and has been trying to convince me to read the archives.

2-3 tbsps white wine vinegar 
1-2 tsps Dijon mustard 
¼ tsp salt, or more to taste 
6 tbsp olive oil 
1 small to medium shallot, minced 
2 lb. small leeks - about 7 or 8 

Optional garnishes
Finely chopped bacon 
Finely chopped hard-boiled egg 

1. In a small bowl, whisk together 2 tablespoons white wine vinegar, 1 teaspoon mustard, and salt. Gradually whisk in the olive oil, mixing until emulsified. Taste. This dressing should be fairly bright, and the mustard flavor should come through, but not too powerfully. Adjust as needed with vinegar, mustard, and/or salt. When you’re happy with it, add the shallots, whisking to blend. Set aside. Be sure to taste it again later, just before tossing it with the leeks, so that if necessary, you can adjust it according to their flavor. 
2. Lay a clean kitchen towel on the counter near the stove. 
3. Bring a large pot of water to a boil, and salt it well. It should taste like sea water. 
While the water comes to a boil, prepare the leeks. Trim away the hair-like roots, but take care not too cut in too far; you want the leek to stay intact. Cut off and discard the dark green leafy parts, leaving just the white and pale green stalk. Starting about 1 inch from the root end, so as to keep the white part intact, cut lengthwise down the middle of the leek. (If you were to splay the cut leek open, it should look like a stubby Y.) Wash the leeks well under running water, flushing any dirt from between the layers. 
4. Boil until they are very, very tender and yield easily to a knife. Their color will become muted, and they may be falling apart a little. That’s okay. To be sure they’re done, taste one: it should taste sweet, with no trace of raw flavor. The amount of time that this will take depends on their size, but it will probably take longer than you think. Ten minutes is a good bet. 
5. Draining the leeks as well as you can, transfer them to the kitchen towel on the counter. Blot and press them dry. (Don’t burn yourself!) 
6. While they’re still hot, put them in a bowl, and toss them with a generous amount of the dressing. Allow to cool at least slightly before serving. 
7. Serve warm or at room temperature, with more dressing spooned on top and a pinch or two of salt. If you want to make it a little fancier, garnish with bacon and/or chopped egg.

Last night, at yet another neighbourhood feast, my neighbour showed me the cookbook she used at school in the 1950s. The pages are spotted with age and splashed with sauces made half a century ago, and the binding is beginning to disintegrate. But the recipes on those pages are a complete guide to the culinary traditions of the Perigord, and of France as a whole, and I am determined to preserve them for posterity.

Over the next few weeks, I shall post as many of the recipes as I can before I am asked to return the book, as it is a perfect introduction to French cuisine for anyone who wasn't taught the fundamentals as a schoolchild.

Today's recipe is the simple and classic celeri remoulade, which formed part of last night's meal. My wife makes huge bowls of the stuff every summer; we eat it at lunch, sitting outside in the courtyard, where plates piled high with ham, cheese, and hunks of torn baguette always seem to have a little space left over for this crunchy, creamy, mustardy salad.

600g celeriac, washed and peeled
130g mayonnaise (homemade or store-bought)
2tbsps Dijon mustard
2tbsps lemon juice
salt and freshly ground black pepper

1. Prepare the dressing. Like many vegetables, celeriac is quick to discolour once exposed to the air, and so the sauce should be made first and then put aside while the celeriac is prepared. To make the dressing, simply mix the mustard, lemon juice, and the mayonnaise together.
2. Grate the celeriac. You can buy special graters for the purpose in France, or you can use the coarse side of a standard cheese grater.
3. Stir the dressing through the grated celeriac until every strand is finely coated. Add salt and pepper to taste.
Serve as a vegetable side dish with almost anything - last night we ate it with roast chicken, but it works well on picnics, in lunch boxes, and with grilled meat and fish.