Prinsesstårta — Sweden's green marzipan princess cake

i. Origin & history

The cake is credited to Jenny Åkerström, a Swedish home economics teacher who tutored Princesses Margaretha, Märtha and Astrid, the daughters of Prince Carl, Duke of Västergötland — Astrid later became Queen of the Belgians. Åkerström published Prinsessornas kokbok ('The Princesses' Cookbook'), first in 1929, with several later editions, and it included a cake originally called grön tårta, 'green cake'. The princesses were said to be particularly fond of it, and it came to be known as prinsesstårta.

The details of exactly when the name changed, and how close the original was to the modern version, vary between accounts. What is clear is that by the mid-twentieth century the green-domed cake had become a standard of Swedish konditorier and a favourite celebration cake, a status it has kept. Today it is bought or baked for birthdays, name days, graduations and anniversaries, and Swedish bakeries sell individual slices and miniature versions every day.

Sweden even has a Prinsesstårtans vecka, a princess-cake week each autumn, promoted by the national association of bakers and confectioners, during which bakeries sell large numbers of the cake. Its iconic colour has also spawned variants: operatårta with pink marzipan and Carmen-tårta with orange.

Prinsesstårta is often compared with Norway's bløtkake and with the marzipan-covered marsipankake. All share a sponge-cream-fruit base, but the princess cake is defined by its high dome of whipped cream inside and the thin, perfectly smooth green marzipan coat.

ii. How the dome holds its shape

The dome is built, not baked. The cake begins as a flat sponge cut into three layers; the bottom layer is spread with jam and thick vanilla custard, the second layer goes on, and then a large quantity of whipped cream is mounded on top and smoothed into a high dome before the final, thinnest sponge layer is draped over it and pressed gently into a curve. The marzipan then covers everything.

The custard has to be thick enough to hold up the layers. It is a classic crème pâtissière — milk, yolks, sugar and cornflour, boiled until thick — often stabilised with a little gelatine in Swedish bakeries, and folded with some whipped cream to lighten it. A runny custard makes the layers slide and the dome slump.

The whipped cream is equally structural. It needs to be whipped to firm, smooth peaks so it can be shaped and support the marzipan, but not so far that it turns grainy. Chilling the assembled cake before covering it lets the cream firm up.

The marzipan must be rolled very thin, around 2 mm, and lifted over the cake in one sheet. Thick marzipan is heavy and cloying and can crush the cream dome; thin marzipan drapes smoothly and gives a delicate layer of almond sweetness. Smoothing it with the palms and trimming the base cleanly gives the polished finish the cake is famous for. Dusting with icing sugar hides any small marks.

iii. Ingredients

Makes 12 servings · scroll the side panel to adjust

• 4 eggs, at room temperature
• 150 g caster sugar, for the sponge
• 90 g plain flour
• 45 g potato starch
• 1 tsp baking powder
• 300 ml whole milk, for the custard
• 3 egg yolks
• 50 g caster sugar, for the custard
• 25 g cornflour
• 1 vanilla pod, split
• 2 sheets leaf gelatine, optional
• 500 ml whipping cream
• 2 tbsp icing sugar, for the cream
• 120 g raspberry jam
• 400 g marzipan, coloured pale green
• 30 g marzipan, coloured pink, for the rose
• 2 tbsp icing sugar, to dust

Ready-coloured green marzipan is sold in Swedish shops; otherwise knead a tiny amount of green gel colour (and a speck of yellow) into white marzipan for the classic pale spring green. Swedish marzipan contains about 50 per cent almonds; higher-almond marzipans are less sweet but more fragile when rolled thin. Potato starch in the sponge gives the fine, tender Swedish crumb. The gelatine is optional but makes the custard firmer and the cake easier to slice. Use a good, seedless raspberry jam.

iv. Method

1. Make the custard: heat the milk with the vanilla pod until steaming. Whisk the yolks, sugar and cornflour, pour on the hot milk while whisking, return to the pan and cook, stirring, until thick and bubbling for 1 minute. Remove the vanilla, stir in the soaked and squeezed gelatine, cover the surface and chill completely.
2. Make the sponge: heat the oven to 175 °C (350 °F), or 155 °C fan, and line the base of a 22–24 cm springform tin. Whisk the eggs and sugar for 8–10 minutes until very thick and pale. Sift in the flour, potato starch and baking powder and fold in gently. Bake for 30–35 minutes until risen and springy. Cool completely, then cut into 3 layers, the top one thinnest.
3. Whip the cream with the icing sugar to firm, smooth peaks. Beat the cold custard until smooth and fold in 4 tbsp of the whipped cream.
4. Place the bottom sponge on a board, spread with the jam, then the custard. Add the middle layer.
5. Pile almost all the remaining whipped cream onto the middle layer and smooth it into a high dome, thickest in the centre. Lay the thin top layer over the dome and press gently to shape it. Spread the last of the cream thinly over the whole cake. Chill for 30 minutes.
6. Dust the work surface with icing sugar and roll out the green marzipan into a circle about 2 mm thick and large enough to cover the cake (about 38 cm across).
7. Lift the marzipan over the cake with the rolling pin, smooth it gently over the dome and down the sides with your palms, easing out any folds, and trim neatly at the base.
8. Shape the pink marzipan into a rose with a couple of green marzipan leaves, place it on top, and dust lightly with icing sugar. Chill for at least 1 hour before slicing with a hot knife.

v. Tips & common mistakes

• Make the custard and sponge a day ahead. Cold, rested components are much easier to assemble, and the sponge slices more cleanly.
• Keep the custard thick. Boil it fully and chill it well; a soft custard makes the cake slide apart.
• Build a tall dome. The cream dome is the shape of the finished cake. Be generous and smooth it carefully before the marzipan goes on.
• Roll the marzipan thin and wide. About 2 mm thick and wide enough to cover the cake without stretching. Thick marzipan is heavy and tears.
• Use icing sugar, not flour, for rolling. Flour leaves white marks and dulls the green.
• Assemble on the day of serving. The marzipan absorbs moisture from the cream and softens; it is at its best within a few hours.

vi. Variations

Operatårta is the same cake with pink marzipan, and Carmen-tårta uses orange marzipan. Prinsessbakelse are individual slices sold in bakeries. Some modern versions add fresh raspberries to the jam layer, replace the jam with lingonberry or strawberry, or flavour the cream with cardamom. Christmas versions sometimes come in red marzipan.

For other celebration cakes from the North, see Norway's bløtkake and almond suksessterte and Sweden's semla. Elsewhere, compare the Hungarian somlói galuska, the British Battenberg cake with its marzipan wrap, and the German Prinzregententorte.

vii. Serving & storage

Serve prinsesstårta chilled, cut into wedges with a long, hot knife, wiping it between cuts. It is served at birthdays, christenings and graduations in Sweden, with coffee in the afternoon or as a dessert after a celebratory meal.

It is best on the day it is assembled. Covered in the fridge, it keeps for up to 2 days, though the marzipan gradually softens and may sweat. It does not freeze well once assembled. The sponge can be frozen for up to 3 months and the custard made up to 2 days ahead.

ix. More from Scandinavian

• Bløtkake — Norwegian cream layer cake
• Suksessterte — Norwegian success cake
• Semla — Swedish cream bun
• Cardamom Bun — Swedish kardemummabulle
• Marzipan — almond and sugar paste
• Battenberg Cake — marzipan-wrapped chequerboard