A simple, budget-friendly French side: leeks gently braised in butter, then finished with Dijon mustard, crème fraîche and a squeeze of lemon.

Cut the leeks in half, then chop into segments. Wash thoroughly.
Melt the butter in a saucepan, add the leeks, stir, cover and cook over very low heat for about 25 minutes, stirring occasionally.
Add the lemon juice, mustard and crème fraîche to the leeks. Season lightly with salt, add pepper and mix well.
Cover and cook for another 10 minutes over low heat.