Hello I recently made the Raspberry Bakewell Slice recipe from Kitchen. However the raspberries made the sponge soggy. What did I do wrong?
Nigella's Raspberry Bakewell Slice recipe (from Feast) is an adaptation of the classic Bakewell Tart, made in "traybake" form and with the addition of fresh raspberries in the filling. We would however mention that the filling is not a sponge cake but a mixture called frangipane. The texture of frangipane is very different to a sponge cake.
Frangipane is made from melted butter, eggs, sugar and ground almonds. When it bakes it will puff up slightly, in a similar manner to a sponge cake, but as the mixture contains ground almonds and no flour it will cool and set as a very damp, almost marzipan-like, filling. The raspberries may let out a little juice, but this tends to mingle with the jam on the base of the tart, rather than affecting the frangipane.
If you would like to try a version without fresh raspberries then Nigella has an alternative Bakewell recipe in Feast (p.222), though this tart also has a frangipane filling.