Apple cinnamon custard cake

INGREDIENTS:

• 20g unsalted butter
• 500-550g (about 3) Granny Smith apples, peeled, cored, cut into 8 wedges, then cut into 1/2 cm thick slices
• 2 tablespoons grand marnier, or other orange liqueur
• 1 1/4 cups plain flour, plus 2 tablespoons extra
• 1 cup caster sugar, plus 1 tablespoon extra
• 2 teaspoons baking powder
• 1/2 teaspoon salt
• 3/4 teaspoon ground cinnamon
• 1 cup canola oil
• 1 cup full cream milk
• 2 large eggs
• 2 teaspoons orange zest
• 1 teaspoon vanilla extract
• 2 large egg yolks
• 1 teaspoon icing sugar, sifted
• 1 cup thickened cream
• 1 tablespoon icing sugar, sifted

INSTRUCTIONS:

• Step 1
  Position a rack in the centre of the oven and preheat to 180C or 160C fan-forced. Grease a 23cm springform pan with the 20g of butter.
• Step 2
  In a medium bowl, toss the apples with Grand Marnier to coat, and set aside.
• Step 3
  In another medium bowl, whisk together the 1 1/4 cups of flour, 1 cup of caster sugar, baking powder, salt and 1/4 teaspoon of the cinnamon. In a large bowl, whisk together oil, milk, whole eggs, orange zest and vanilla to blend. Whisk dry ingredients into the wet ingredients to form a smooth batter. Be careful not to over-mix.
• Step 4
  Transfer 1 cup of the batter to a small bowl and mix in the remaining 2 tablespoons flour; set aside. Whisk egg yolks into remaining batter in the large bowl just to blend. Stir in the apples. Transfer the apple batter to prepared pan and, using a crank-handled spatula, spread batter into an even layer and press the apples in to submerge them. Pour the reserved batter evenly over the apple batter. In a small bowl, whisk the remaining caster sugar and cinnamon to blend, and then sprinkle it evenly over the batter.
• Step 5
  Bake for 50 mins, or until a skewer inserted into the centre of the cake comes out clean and the top is golden brown. Transfer the pan to a wire rack and cool for 15 mins. Run a knife around the sides of the cake and release the pan sides. Cool cake for about 30 mins to serve warm, or cool completely. Dust with icing sugar.
• Step 6
  To make whipped cream, in a medium bowl, whisk cream and icing sugar until thick. To serve, cut cake into wedges and serve with a generous dollop of whipped cream.