Heat oven to 180C/160C fan/gas 4.
Butter and line a 20 x 30cm traybake tin
with baking parchment.
Put the butter, caster sugar, flour,
eggs and orange zest in a bowl. Beat
thoroughly with an electric whisk until
creamy and smooth. Stir in the
gooseberries, then spoon into the tin
and level the surface. Bake for 35 mins
until a skewer inserted into the cake
comes out clean.
Stir the orange juice and granulated
sugar together, spoon over the surface
of the warm cake and leave to cool and
set. Cut into squares.