Schaum Torte

This is a high-sugar meringue in the German-American style: about a third of a cup of sugar per egg white, which gives a crisp shell and a chewy, marshmallow-like center. The instruction that matters most is the oven.

• Oven, honestlyA "moderate oven" in books of this period is usually reckoned at roughly 350-375F, and a meringue held there for an hour will color deeply and crack. Meringue of this sugar ratio is normally baked at 275-300F for an hour to an hour and a half, then left in the turned-off oven to dry.
• Sugar added graduallyBeat the whites to soft peaks first, then add the sugar a tablespoon or two at a time. Rub a little between your fingers before it goes in the oven; any grittiness means undissolved sugar, which weeps out as syrup during baking.
• The vinegarOne teaspoon of vinegar or lemon juice is an acid stabilizer. It lowers the pH of the whites so the foam tolerates the large amount of sugar without collapsing. Cream of tartar, a scant half teaspoon, does the same job with no flavor.
• The panGrease sparingly, or better, line with parchment. A heavily greased pan lets the meringue slide and slump as it sets. A springform or a pan with a removable base makes it possible to get the torte out intact.
• Baked in layersFor the layered version, pipe or spread the meringue into two or three rounds on parchment. Thin layers need only 45 minutes to an hour at the low temperature, and they are easier to serve than one thick torte.
• "Gelatine between"This means a set fruit gelatin or a gelatin-stabilized cream used as a filling. Fill no more than an hour or two before serving; meringue draws moisture and softens quickly once anything wet touches it.
• YieldSix egg whites and two cups of sugar make a substantial torte. Eight servings is realistic, particularly with whipped cream; the stated four is generous by any modern measure.
• HumidityMeringue is unreliable on a damp day. It will take longer to dry and may stay tacky on the surface no matter how long it bakes.