Raspberry Sauce

This is not the typical thick raspberry coulis you spoon over cheesecake. This is a British custard-style sauce, more akin to a fruit-flavored zabaglione, whipped over gentle heat into a light, frothy cloud of pink that drapes over hot puddings and warm sponge cakes.

The technique is closer to making a sabayon than a coulis. Eggs and a small amount of flour-paste thickener whisk continuously over very low heat with the raspberry juice and sugar, slowly transforming into a foamy, almost-soufflé-light sauce that triples in volume. It’s served the moment it thickens, before it can deflate.

Keeping the heat extremely low is critical. The eggs scramble if the temperature gets anywhere near boiling, ruining the sauce. A double boiler is the safest approach for home cooks who don’t fully trust their stove’s lowest setting.

The flour paste is an old-school stabilizer. Just a tablespoon or two mixed with cold water before going in keeps the egg foam from collapsing as it cools slightly. Modern cooks might skip it, but the original Edwardian recipe uses it for good reason.

Using real raspberry juice (the strained liquid from cooked fresh or frozen raspberries) gives the sauce its true character. Bottled raspberry syrups are too sweet and one-note for this. The actual fruit juice has the right acidity and depth.

Pro Tips

• Use a balloon whisk and keep moving the eggs constantly, the moment you stop whisking, you risk scrambling
• Test for doneness when the whisk leaves a momentary trail in the sauce, that’s the signal it’s thickened enough
• Serve immediately over warm dessert, the sauce begins deflating within minutes off the heat
• For best raspberry juice, simmer 2 cups of fresh or frozen raspberries with a splash of water for 10 minutes, then strain through a fine sieve

Variations

• Swap raspberry juice for strawberry, blackberry, or red currant juice for different berry sauces
• Add a tablespoon of brandy, kirsch, or framboise for a boozy, more complex version
• Use this as a pudding sauce over sponge cake, warm chocolate cake, or vanilla ice cream