Heat the oven to 180C/160C fan/gas 4. Put the sultanas and teabags in a heatproof bowl and cover with boiling water from the kettle. Leave to steep for 5 mins, then remove and discard the teabags. Leave the sultanas to continue soaking while you prepare the cake mixture. The sultanas can be soaked ahead of time; steep with the tea as above, then leave to soak, covered, overnight.

Beat the butter and sugar together in a large bowl for 3 mins, or until smooth and pale. Add the eggs, one at a time, beating well between each addition and scraping down the sides of the bowl until combined. Add the flour, baking powder, almonds and lemon zest, and mix briefly to combine. Fold in the milk to loosen. Drain the rehydrated sultanas, discard the tea, then fold the sultanas into the mixture.

Generously butter a 25cm, 2-litre bundt tin. Pour in the mixture and level with a spatula. Bake in the centre of the oven for 35-40 mins, or until golden brown and a skewer inserted into the middle comes out clean. Invert the tin onto a serving plate, leave to cool for 5 mins, then lift off the tin. Leave to cool completely, and dust lightly with icing sugar. Will keep for up to three days in an airtight tin.