Cream Tomato Sauce

A two-line finishing instruction that depends entirely on a tomato sauce made elsewhere in the book. The whole point is the last sentence.

• Never boil itCream added to an acidic tomato base will curdle if it reaches a simmer. Pull the pan off the heat, stir the cream in, and serve within a few minutes; if it must be held, keep it below about 160F over hot water.
• What "thick cream" meansIn this period the term generally meant the richer top cream skimmed from unhomogenised milk, which stood closer to modern heavy or double cream than to table cream, though the actual fat content varied. Light cream or half-and-half is likelier to break in acid.
• Three tablespoonfulsOne tablespoon short of a quarter cup, meant to enrich and pale the sauce rather than turn it into a cream sauce. The recipe gives no quantity for the base tomato sauce, so scale the cream to taste.
• Guard against splittingWarming the cream slightly and stirring it in off the heat, rather than pouring it cold into a hot pan, gives a smoother result. A very acidic or long-reduced tomato base is the most likely to break.
• The base sauceThe referenced tomato sauce is not reproduced here. Tomato sauces in books of this era were often tomatoes cooked down with onion and seasoning, thickened with a butter-and-flour roux and strained; if yours is thickened that way, the starch will help hold the cream, whereas a purely reduced base is more prone to break.