Zesty Orange Marmalade Upside-Down Cake

Preheat your oven to 180°C (160°C fan/gas 4) and generously grease a 23cm round cake tin with butter. Finely zest the oranges and set the zest aside. Using a sharp serrated knife, remove the remaining peel and white pith from the oranges. Slice the oranges into 1cm-thick rounds, sprinkle 25g of the golden caster sugar over the base of the tin, and arrange the orange slices on top.

Prepare the syrup by weighing the reserved orange peels and pith into a small saucepan. Add an equal weight of sugar and water (approximately 100g of each). Bring the mixture to a simmer, then boil for about 10 minutes until the liquid has reduced and thickened into a syrupy consistency. Set aside to infuse, then strain through a sieve.

In a large bowl or stand mixer, cream the 200g of softened butter and the remaining 200g of sugar together for about 5 minutes until the mixture is pale and fluffy. Beat in the eggs one at a time, ensuring each is fully incorporated before adding the next. Stir in the reserved orange zest and the marmalade.

Gently fold in the self-raising flour and a pinch of salt using a large metal spoon until just combined. Spoon the batter over the orange slices in the tin and smooth the top with a spatula. Bake for 35–40 minutes, or until the cake is golden brown and a skewer inserted into the center comes out clean.