Preheat oven:
Preheat to 170°C (fan) / 190°C (no fan)
→ That’s 340°F (fan) / 375°F (no fan)
Prepare batter:
In a bowl, beat 8 eggs until fluffy. In a separate bowl, mix 200g sugar with a pinch of salt. Gradually add the sugar to the eggs, a spoonful at a time, beating for 3–5 minutes until thick and voluminous.
Combine dry ingredients:
Mix together almond meal, cornflour, baking powder, and citrus zests. Fold into the egg mixture a quarter at a time, being gentle to maintain airiness. I like using a spatula for this.
Bake:
Pour batter into prepared tin and bake for 35–40 minutes. After 20 minutes, cover loosely with foil if browning too quickly. Cake is ready when a skewer comes out clean.
Cool and prepare filling:
Remove cake from tin and peel off baking paper. Allow to cool completely — cake may sink slightly in the centre, that's normal.
Toast almond meal for sides:
In a dry pan, toast 100g almond meal over medium-low heat, stirring constantly until golden. Let cool.
Whip the cream:
Whip cream until thick, then add icing sugar and orange zest. Whip again until firm but spreadable.
Slice and fill:
Slice cake into two even layers. Spread marmalade and about ¼ of the cream on the bottom layer. Add second layer, repeat with marmalade and another ¼ of the cream. Use remaining cream to cover top and sides.
Decorate:
Press toasted almond meal around the sides. Top with overlapping slices of orange. Chill for 2 hours before serving.
Chill for at least 2 hours before slicing.