BUTTER
Use unpasteurised butter (made from cream that has not undergone any treatment) – if it is available – or pure pasteurised butter. It contains about 82 per cent fat. Butter provides taste, creaminess and crumbliness to mixtures. For mixtures that will be salted (generally to enhance the flavours), use unsalted butter so that you can control the salt content more precisely.
In certain mixtures, such as sablé pastry, the butter must be very cold when it is incorporated into the other ingredients. It must not be completely mixed into the flour. The little pieces of butter that remain in the pastry will form air pockets during baking, giving the pastry its crumbly texture.
The melting point of butter varies according to the season it is produced and the food the cows eat. The butter produced in winter is hard and its melting point is elevated (above 32°C); this butter is called ‘dry’. It is used for pastries, in particular those involving turning and folding (people also call it ‘turning butter’), because it can be worked for longer. You will find it in specialist pastry supply stores.
This operation consists of rendering butter or a mixture of butter and sugar airy and creamy by whisking it vigorously. Generally start with softened butter.
This is butter softened and worked until it takes on the consistency of a cream before being incorporated into a mixture. It helps avoid lumps and provides creaminess.
Cut the butter into pieces, let it soften at room temperature or soften it by applying gentle heat (without letting it melt, or it will lose its creaminess), then work it into a smooth cream using a spatula or whisk.
This is gently heated butter, from which the water evaporates and which takes on a hazelnut colour (which is why the French call it ‘beurre noisette’). It is the casein (the protein in butter) that colours the butter and gives it its taste.