Dried mushrooms, yeast extract and a spoon of cornflour make a gravy dark enough and savoury enough to carry a plate of polenta, which on its own is not much.
Start the mushrooms first and keep the water. Twenty grams of dried mushrooms in 400 ml of just-boiled water gives you both the mushrooms and the best liquid in the cupboard. Pouring that away is the mistake to avoid.
- Mushrooms into the hot water. Fifteen minutes, covered. Lift them out and chop them; let the liquid settle and leave the last spoonful behind, which is where the grit goes.
- Oil in the pan, dried onion and the chopped mushrooms, four minutes over a moderate heat until the onion has gone sweet and the mushrooms have taken a little colour.
- Mushroom liquid in. Yeast extract dissolved into it. Simmer five minutes.
- Slake the cornflour in two tablespoons of cold water and stir it in off the boil. Back on the heat, stir, and it thickens in under a minute. Pour it into a mug and set aside.
- Same pan, rinsed. Polenta according to its packet, which is usually one part polenta to four of water, five minutes of steady stirring.
Polenta sets as it cools and stops being pourable within a couple of minutes, so have the gravy ready before the polenta is, not the other way round.
Pepper hard at the end. The gravy is salty enough already.