Moravian sugar cake

Method

1. Lightly grease a 20cm diameter cake tin with butter or flavourless oil. Put the potato pieces in a small saucepan, then add enough water to cover by 5cm. Put the pan over a medium-high heat and boil until the potato almost falls apart when pierced with the tip of a knife (about 10 minutes). Drain the potato, reserving 60ml of the cooking water, then return to the still-hot pan and shake to dry the potato a bit.
2. Using a handheld electric mixer, mash the potato in the pan until smooth (you can use a potato ricer if you prefer). Measure out 110g of the mashed potato into a small bowl, then add the reserved cooking water and whisk until smooth (see Shauna’s tips).
3. In a medium bowl, whisk together the flour, yeast, cinnamon, nutmeg and salt. In a separate large bowl, beat together the butter, evaporated cane juice (or similar) and orange zest with an electric mixer on a medium speed for 2 minutes or until creamy. Add the egg and beat until smooth and aerated. Beat in the vanilla extract. Turn the mixer speed to low, then add the flour mixture and the whisked potato mixture in 5 alternating additions (see Shauna’s tips), beginning and ending with the flour.
4. When the dough is smooth and combined, lightly dust a work surface with plain flour. Scrape out the dough onto the work surface. Flour your hands and knead the dough several times – it will still look a bit shaggy. Drop the dough into the prepared cake tin and press it into an even layer with your fingers. Cover the cake tin with cling film, then set aside in a warm place for 1 hour to 1 hour 30 minutes or until the dough has doubled in volume.
5. Heat the oven to 180°C/160°C fan/ gas 4. Make the topping: in a small bowl, fork together the muscovado sugar, cinnamon and orange zest with a pinch of fine sea salt.
6. Dip both index fingers in some plain flour, then poke 12-15 holes all over the surface of the dough, about 3cm apart, burrowing all the way to the bottom of the tin. Swirl the tips of your fingers around in the dough to encourage the holes to stretch a bit and stay open. Fill each hole with a few pinches of the sugar mixture (don’t pack it in – drop it in lightly). Scatter the rest of sugar topping over the surface of the dough. Use a pastry brush to lightly dab and drizzle the cooled melted butter evenly over the surface.
7. Put the tin on the middle oven rack and bake for 30 minutes or until the cake is puffed and golden and a skewer pushed in comes out clean. Cool in the tin on a wire rack before turning out onto a platter or cake stand and serving.