Peel the onions, cut in half and slice as thinly as possible. Melt the butter in a heavy-based saucepan; when foaming, add the onions and cook for 2½–3 hours over a very low heat until all the juice has evaporated. The onions will caramelise and take on a deep, golden brown colour. Season to taste with salt and freshly ground pepper. If not using immediately, spread the onions on a tray and refrigerate to cool. Reheat over a very low heat when ready to use. Adjust the seasoning if necessary.
© 2005 Liam Tomlin. All rights reserved.