Diótorta

Ingredients

• 6eggfor the sponge, separated
• 7 ozsugarfor the sponge
• 4¼ ozflourfor the sponge, a little extra for the tin
• 2¾ ozwalnutsground, for the sponge
• ⅓ ozbaking powder1 sachet, for the sponge
• 1 pinchsaltfor the egg whites
• 7¾ ozwalnutsground, for the filling
• 1 cupmilkfor the filling
• 6⅓ ozsugarfor the filling
• ½ ozvanilla sugarabout 2 sachets, for the filling
• 5¼ ozbuttersoftened, for the filling; a little for greasing the tin
• 1⅓ tbsprumto flavour the filling
• 3½ ozdark chocolatemelted, for decorating
• walnutsfor decorating (optional)

Method

1. Whip the whites, prep the tinSeparate the eggs and whisk the whites with a pinch of salt until stiff. Preheat the oven to 160–355 °F, then grease a 26 cm springform tin with butter and dust it with flour, or line it with baking paper.
2. Mix the nutty batterBeat the yolks with the sugar for the sponge until pale and fluffy. Mix the flour with the baking powder and the ground walnuts for the sponge, then stir this into the yolk mixture.
3. Fold in the whites and bakeGently fold in the beaten egg whites so the batter stays nice and airy. Pour it into the tin and bake the sponge for 35–40 minutes; a skewer test will tell you when it's done.
4. Cool the spongeLet the sponge cool completely on a wire rack before you do anything else with it.
5. Cook the nut mixtureFor the cream, bring the milk to the boil with the sugar and vanilla sugar, then pour it over the ground walnuts. Leave the nut mixture to cool.
6. Whip up the buttercreamBeat the softened butter until fluffy and mix it with the cooled nut mixture. Season the cream with rum to taste.
7. Fill and cover the torteCut the sponge horizontally into layers. Sandwich the layers with the walnut cream, then spread the rest of the cream over the top and sides of the torte.
8. Decorate, chill, sliceDecorate the torte with melted dark chocolate or walnut halves. Chill it for a few hours, then cut it into slices.

Tips and variations

The filling is easy to play with: instead of walnut cream, try a chestnut cream with rum and butter, a chocolate cream made from ganache and whipped cream, or orange marmalade between the layers, and if you like, cover the whole torte with a layer of marzipan. You can also bind the walnut cream with boiled, puréed potatoes and chop some of the nuts roughly instead of grinding them, which gives it more bite. Another version of the sponge uses only a little flour and adds breadcrumbs and bicarbonate of soda to the batter; for this one, the whites are whisked stiff with the sugar first and the yolks stirred in one at a time. A few tablespoons of water in the yolk mixture make the batter even lighter. Serve the torte well chilled so it cuts into clean slices.