There is something so satisfying about making a cake the old-fashioned way, with a big bowl and a wooden spoon, and that’s all you need here to create this amazing treat of vanilla and orange-chocolate sponge cake. By putting the two batters into the pan in a bulls-eye pattern, the cut cake does indeed look like a zebra: it isn’t difficult, just give yourself a little extra time. It’s fun to make, fun to look at, and such fun to eat!
1 cup vegetable oil, plus a little extra for greasing
9 oz. caster sugar (scant 1½ cups)
3 fl. oz. semi-skimmed milk
4 medium eggs (or 3 large)
10½ oz. self-rising flour, divided as directed below
1 tsp. baking powder, divided
1 oz. cocoa powder
zest of 1 orange
Heat the oven to 350°F. Grease the bottom of a 9″ round springform pan, line with a circle of parchment paper, and oil again.
Combine the oil, sugar, milk, eggs, and vanilla in a large bowl, beating everything together well with a wooden spoon. It is best not to use an electric mixer, as it will introduce too many bubbles. Transfer half of the mixture to another bowl. To this bowl sift in 1¼ cups plus 2 tbs. of the flour and ½ tsp. of the baking powder. Mix well and set aside. This will be the vanilla mixture.
To the remaining batter, sift in the rest of the flour and the baking powder, along with the cocoa and the orange zest, and mix well. This is the chocolate mixture.
Put a tbs. of the vanilla batter in the center of the pan. Then, using a clean spoon, put a blob of the chocolate batter in the middle of the vanilla circle. Continue alternating the batters in the same fashion. The bulls-eye will gradually spread out and reach the edges when all the batters are used. (We found this process most easily accomplished by putting the two batters in separate pastry bags and piping in the bulls-eye.)
Bake for 35-45 minutes, or until a cake tester comes our clean. Leave to cool in the pan for a few minutes, then turn out onto a wire rack to cool completely.