Zimtsterne

Method

1. Whisk the egg whites with the salt until they hold a soft peak. Add the sifted powdered sugar a spoonful at a time with the mixer running, then beat another 4 to 5 minutes until the meringue is thick, bright white, and glossy, and a lifted whisk leaves a peak that folds over slowly at the tip. This is a cold-set royal-icing style meringue; underbeaten it will never dry properly on the biscuit.
2. Take out 90 g of the meringue, about 5 rounded tablespoons, and put it in a small bowl. Press cling film directly onto its surface. This is the glaze. If you forget this step you cannot recover it, because once the almonds go in there is no getting them out.
3. Stir the cinnamon and the rum into the remaining meringue, then fold in the ground almonds in three additions. It will go from a foam to a heavy, sticky, marzipan-like mass. Fold only until the last dry almond disappears.
4. Scrape the dough onto cling film, flatten it to a slab about 2 cm thick, wrap it, and chill 1 hour. It must be cold or it cannot be rolled.
5. Dust the work surface generously with powdered sugar, not flour. Put half the dough down, dust the top, lay a sheet of cling film over it, and roll to 8 mm. Work in two batches and keep the second half in the fridge.
6. Cut the stars. Dip the cutter in powdered sugar between every single cut. If you skip this the points tear off inside the cutter and you will lose a third of them. Lift each star with a small palette knife onto a parchment-lined tray, leaving 2 cm between them.
7. Knead the offcuts together gently, chill 10 minutes, and reroll. The second rolling is fine. By the third the dough has picked up too much powdered sugar and bakes hard, so make the last few by hand.
8. Brush the loose powdered sugar off the top of each star with a dry pastry brush before you glaze. Sugar left on the surface dissolves under the wet glaze and creates a slip layer that slides the glaze off in the oven.
9. Glaze with a small brush, working from the centre out to each point, in a thin even coat that stops 1 mm short of the edge. Do not pipe it and do not build ridges. A brush pushes the air out; a piping bag leaves a thick shell that cracks as the biscuit expands.
10. Let the glazed stars stand 20 to 30 minutes at room temperature until the surface is matte and dry to a light touch. Now heat the oven to 140°C top and bottom heat, or 120°C fan.
11. Bake on the middle shelf 12 to 15 minutes at 8 mm thickness. The glaze must stay white. The stars should still feel soft, almost raw, in the middle when you take them out, and the undersides should give slightly under a fingertip.
12. Slide the parchment off the hot tray onto a rack and leave them to cool completely on the paper. They firm up as they cool. Peel them off only when cold.
13. Store airtight, ideally with a slice of apple in the tin, for at least two days before eating. They are chewiest from day two to day ten.

Notes

• The oven runs at 140°C, not the 175°C to 190°C you would use for any other biscuit, and both halves of the recipe demand it. The glaze is meringue: egg white and sugar. Above roughly 150°C the sugar starts to colour, and a Zimtstern with a beige glaze looks like a mistake, which is what most home versions are. Below that the glaze only dries, which is what it is meant to do. The biscuit needs the low temperature for a different reason. There is no flour and no gluten in it, so there is no protein network setting into a crumb. What holds the star together is sugar and the moisture bound in the ground almonds, and the texture you want, chewy inside and only just firm outside, is a moisture level, not a doneness. At high heat the outer 2 mm dries and hardens before the centre has set at all, and you get a shell of nut brittle around a damp core, which then cools into something you could break a tooth on. At 140°C the moisture leaves slowly and evenly, and the whole star lands in the same place. If in doubt, take them out early. They set on the rack.
• The single most common failure is baking them until they look done. They do not look done. They look underbaked, and they should. A Zimtstern that felt firm coming out of the oven will be hard by the next morning.
• Sticky dough is not a fault in the recipe, it is what the recipe is. There is no flour to absorb anything, so the only dry ingredient is sugar and the only structure is chilled fat from the almonds. Three things fix it: chill it properly, roll it under cling film so nothing touches the rolling pin, and use powdered sugar rather than flour or extra almonds on the bench. Flour would technically work but it ruins the point of a gluten free biscuit and it bakes in as a chalky layer. If the dough still fights you after all that, put the wrapped slab in the freezer for 15 minutes, then roll it straight from there.
• Glaze that slides off, glaze that cracks, and glaze that browns are three different problems. It slides when there is loose powdered sugar under it, or when the glaze is too thin because the meringue was underbeaten. It cracks when it goes on too thick, when it is piped rather than brushed, or when the star was rolled thicker than about 1 cm and rises unevenly. It browns when the oven is too hot or the tray sits too high. Give the glaze 20 minutes to set before it goes in the oven and most of this stops happening.
• Thickness is the other lever. Under 6 mm and there is not enough interior to stay chewy, so they dry to crisp. Over 1 cm and the centre stays wet and the glaze splits as the star puffs. 8 mm is the number.
• These contain no flour and no grain of any kind, by construction rather than by substitution, so they are genuinely useful when you have coeliac guests at the Christmas table. Two things to check: German Puderzucker sometimes carries added starch, which is usually maize but is worth reading the packet for, and ground almonds are frequently milled on shared equipment, so buy a bag that is labelled for it if it matters medically.
• Use unblanched ground almonds. The skins carry most of the almond flavour and they give the darker crumb under the white glaze, which is the whole visual point. Hazelnuts or a half-and-half mix are both traditional and both good, though hazelnut pushes the biscuit towards Nussstern territory.
• Cinnamon type matters more here than anywhere else, because there is nothing else to hide behind. Ceylon cinnamon is milder, sweeter, and more floral. Cassia, which is what most supermarket cinnamon is, is hotter and more one-note, and it also carries a lot more coumarin, which the German Federal Institute for Risk Assessment has flagged for exactly this sort of Christmas baking where people eat a lot of it in December. Ceylon costs more and is worth it.
• The rum is optional and does not make them taste of rum. It loosens the dough very slightly and rounds the cinnamon off. Kirschwasser does the same job.
• The dough can be made a day ahead and kept wrapped in the fridge. Let it sit 20 minutes at room temperature before rolling or it will crack at the edges.

Sources used

• Dr. Oetker: Zimtsterne
• Lecker: Zimtsterne nach Uromas Rezept
• Schlaraffenwelt: Zimtsterne in Perfektion, die ultimative Plätzchen-Anleitung