There’s no debate here – this one’s definitely a cake! Make sure to use a good quality no-peel Seville orange marmalade, such as Waitrose or Tiptree, as they have a better flavour and texture than ones made with sweet oranges
Nice idea, but Jaffa cakes are vegetarian, maybe try using agar agar.
Looks great!
Put all the cake ingredients in a large bowl, then use an electric handwhisk to beat them together until just combined and smooth (about 30sec). Tip mixture into prepared tin, smooth to level and bake for 45-50min, or until risen, golden and a skewer inserted into centre comes out clean. Allow to cool in tin completely.
Remove cake from tin, peel off parchment and level-off domed top with a serrated knife. Invert cake on to a board or serving plate so the bottom of the cake becomes the top.
Spread a little marmalade all over top of cake. Carefully unwrap jelly and use clingfilm to help you flip it on to the top of the cake. Press down gently to stick. Trim off any overhang with a sharp knife.
Put chocolate in a heatproof bowl set over a pan of gently simmering water, stirring occasionally until melted and smooth (don’t let the bottom of the bowl come in contact with the water). Remove from heat and stir oil in really well. Leave to cool for 5-10min, until chocolate is room temperature and no longer feels warm when you spoon a drop on your finger.