Golden Sauce

A hard sauce for hot steamed and baked puddings, coloured and faintly scented with marigold. The written ingredient list gives only the flavourings, so the body of the sauce — creamed butter and sugar, thinned with boiling water and thickened over hot water — has to be supplied from the method.

• What "cream everything together" assumesThe recipe names no fat, sugar or egg; creaming and cooking over hot water suggest a base of softened butter and sugar, possibly with an egg yolk, but this has to be inferred. One plausible reconstruction would be 1/2 cup butter, 1 cup sugar and an egg yolk, creamed, then let down with 2-3 tablespoons boiling water.
• Which marigoldThe culinary flower is Calendula officinalis, pot marigold, not the bedding Tagetes sold in garden centres. Pull the petals free of the green base, which is bitter and resinous.
• A fistfulLoosely packed petals compress to very little — reckon a fistful at somewhere between a quarter and a half cup, the petals of several open heads. They bruise into the butter rather than dissolve, so the sauce is likely to end up flecked gold rather than uniformly coloured.
• Unsprayed flowers onlyFlorist and nursery flowers are routinely treated with systemic pesticides that do not wash off. Use blooms from your own garden or from a grocer selling flowers labelled for eating.
• Kumquat peelA "fleck" means a paring of zest, not a slice of whole fruit. Kumquat rind is sweet where lemon rind is not, so a lemon substitution wants slightly less.
• The double boiler is the hingeKeep the water below the bowl at a bare simmer and never let it touch the base. If there is yolk in the sauce it curdles above roughly 180F, and a butter-and-sugar sauce taken too hot will simply split into an oily pool.
• ColourSome of the colour passes from the petals into the warm butter fairly quickly. Longer cooking is unlikely to deepen it.
• Yield and servingA sauce built on 1/2 cup butter and 1 cup sugar makes something over a cup, enough for roughly six servings. Spoon it over the pudding hot, straight from the pan; it stiffens as it cools.