Brown butter is the cheapest upgrade in your kitchen

Brown butter costs nothing and changes almost everything it touches. It is regular butter, cooked until the milk solids toast. The result tastes of hazelnut and caramel, and it makes biscuits, pasta, vegetables and icing taste like someone who knows what they are doing made them.

How to do it

Use a light-coloured pan. Stainless steel or a pale enamel base lets you see the colour, and colour is the entire game. In a black cast-iron pan you are guessing.

Melt the butter over medium heat. It will foam, then quieten, then foam again. That second foam is water leaving, and it means you are close. Swirl the pan, do not stir. Watch the specks at the bottom: the moment they turn the colour of a walnut and the smell turns nutty, take it off the heat.

Pour it immediately into a cool bowl, solids and all. The pan holds enough heat to take it from perfect to bitter in about twenty seconds.

Where to use it

• Cookies. Brown the butter, then chill it back to a soft solid before creaming. Skipping the chill gives you flat, greasy cookies.
• Pasta. Brown butter, a spoon of pasta water, sage, black pepper, and a hard cheese. Dinner in the time it takes the pasta to cook.
• Roasted vegetables. Toss cauliflower or sprouts in it after they come out of the oven, not before.
• Icing. Replace the butter in a buttercream. Nothing else changes.
• Anything with eggs. Fried eggs, scrambled eggs, omelettes.

The one adjustment to remember

Browning drives off water, so you lose roughly 15 to 20 percent of the weight. In a recipe where butter is structural, like shortbread or a cake batter, weigh it after browning and top it up with a splash of water or milk to get back to the original weight.

In anything sauced or finished, ignore this entirely and use it as it comes.

What burnt looks like

Dark brown, almost black specks, and a smell that reads as scorched rather than nutty. Do not try to rescue it by adding more butter. Wash the pan and start again. It takes nine minutes.