This section is from the book "Apicius Redivivus; Or, The Cook's Oracle", by William Kitchiner. Also available from Amazon: The Cooks Oracle.
Keep a pint stewpan for this purpose only.
Cut two ounces of butter into little bits, that it may melt more easily, and mix more readily; put it into the stewpan with a teaspoonful of flour, and a tablespoonful of milk. When these are well mixed, add three tablespoonsful of water; hold it over the fire, and shake it, (all the while the same way,) till it just boils up. It should be of the thickness of good cream.
This, we think, is incomparably the best way of preparing melted butter. The milk mixes with the butter much more easily, and more intimately than water alone can be made to do, and it looks smooth and fine like cream. If it is to be mixed at table with savoury essences, catsup, or cavice, etc, it should be made thicker than if made merely to pour over vegetables.
Clarified butter is best for this purpose; but if you have none ready, put some fresh butter into a stewpan over a slow clear fire; when it is melted, add fine flour sufficient to make it the thickness of paste; stir it well together with a wooden spoon for twenty minutes, till it is quite smooth, and the colour of a guinea: pour it into an earthen pan, and keep it for use. It will keep good a fortnight in summer, and a month in winter. The bigness of a walnut will generally be enough to thicken a quart of gravy.
This in the French kitchen is called roux Be particularly attentive to the making of it; if it gets any burnt smell or taste, it will spoil every thing it is put into. When cold, it should be thick enough to cut out with a knife, like a solid paste. It is a very essential article in the kitchen, and is the basis of consistency in most made dishes, soups, sauces, and ragouts: if the gravies, etc are too thin, add this thickening, more or less, according to the consistence you would wish them to have. In making thickening, the less butter, and the more flour you use, the better; they should be thoroughly worked together, and the broth, or soup, etc. you put them to, added by degrees, and take especial care to incorporate them well together, or your sauces, etc. will have a disgusting, greasy appearance; therefore, after you have thickened your sauce, add to it some broth, or warm water, in the proportion of two tablespoonsful to a pint, and set it by the side of the fire, to raise any fat, etc. that is not thoroughly incorporated with the gravy, which you must carefully remove as it comes to the top. This is called cleansing, or finishing the sauce.
*** Half an ounce of butter, and a tablespoonful of flour, are about the proportions for a pint of sauce, to make it as thick as good cream.
Put a quarter of a pound of butter into a stew-pan with the meat of half a dozen anchovies, three eshallots, and four large blades of pounded mace; stir together, and by degrees add as much flour as will make it a stiff paste; put it into a pot, for the purpose of heightening the flavour of your brown sauces.
The cook will vary the spices, etc according to the taste of those she works for.
Put the butter in a nice clean stewpan, over a very clear slow fire, watch it, and when it is melted, carefully remove the buttermilk, etc. which will swim on the top; let it stand a minute or two for the impurities to sink to the bottom, and then lay a tammis in a sieve, and pour the clear butter through it, into a clean basin, leaving the sediment at the bottom of the stewpan.
Butter thus purified, will be as sweet as any marrow, and is a very useful covering for all potted meats and fish, and equal to the finest Lucca oil for frying fish, and many other culinary purposes.
Put two ounces of fresh butter into a small fry-ingpan, and when it becomes a dark brown colour, add to it a tablespoonful and a half of good vinegar, and a little pepper and salt.
This is used as sauce for boiled fish, or poached eggs.
Wash some parsley very clean, put a teaspoonful of salt into a pint of boiling water, and boil the parsley two or three minutes, drain it on a sieve, and mince it quite fine. The delicacy and excellence of this sauce depends upon the parsley being minced very very fine; put it into a sauce boat, and mix with it by degrees about half a pint of good melted butter.
Be careful to pick the parsley off the stalks before you boil it.
 
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