Method

• 1.
  For the candied citrus, combine sugar and 1L (4 cups) water in a large saucepan over medium-high heat and cook, stirring, until sugar is dissolved. Remove from heat.
• 2.
  Use the wide blade of a zester to cut long strips of peel from two oranges and two lemons. Place strips in a small saucepan, cover with cold water, and bring to the boil over medium-high heat. Strain peels and repeat (this process will remove all bitter white pith from the citrus). Thinly slice remaining orange and lemon.
• 3.
  Bring sugar syrup to the boil and add citrus strips and slices. Simmer for 1 hour or until translucent (see note). Turn off heat and let citrus cool in the syrup. Place 2 racks over 2 baking trays and line one rack with baking paper. Once strips and slices are cool, use tongs to transfer slices to the paper-lined rack and strips to the other rack to drain. Reserve syrup.
• 4.
  In a large bowl, gently toss orange and lemon strips in the extra sugar. Tap off excess sugar and return to rack. Repeat with a fresh batch of extra sugar. Stand strips and slices at room temperature for 6-8 hours or overnight until set. Preheat oven to 175°C/155°C fan-forced.
• 5.
  Grease a 22cm round cake pan and line with baking paper. Place sugar and orange zest in a stand mixer fitted with the paddle attachment and beat to perfume the sugar. Add butter and beat on medium-high speed for 2-3 minutes until light and fluffy. Add egg yolks and beat, scraping down sides of bowl with a rubber spatula as required, for 4-5 minutes until pale and thick. Sift flour, baking powder and 1/4 tsp salt flakes over batter, then fold with a large spatula, gradually adding milk and juice until just combined. Transfer to a large bowl.
• 6.
  Clean and dry mixing bowl thoroughly. Place egg whites in the clean bowl of stand mixer fitted with the whisk attachment and whisk until stiff peaks. Using a large rubber spatula, fold 1/3 of egg white through batter to loosen, then carefully fold through remaining egg white until just combined (do not overmix or batter will deflate).
• 7.
  Pour into prepared pan and level top with a spatula. Bake for 1 hour or until a skewer inserted into centre of cake comes out clean. Set the pan on a wire rack and allow to cool completely. Place cake on a plate or cake stand and drizzle with a little citrus syrup. Top with whipped cream, then decorate with some candied orange slices and strips. Serve with remaining syrup and candied citrus alongside.