
Cream butter then sugar. Beat in eggs one at a time, then vanilla. Beat in dry ingredients, stir through apple. Bake in 23cm/9" pan at 180°C/350°F (160°C fan) for 30 minutes.
Preheat the oven to 180°C/350°F (160°C fan-forced).
Cake pan – Butter a 23cm/9" round cake pan and line the base with baking paper / parchment paper. No need to line the sides.
Dry ingredients – In a separate bowl, whisk together the flour, baking powder and salt.
Cream butter and sugar – Using a handheld beater or stand mixer with the paddle attachment, beat the butter for 1 minute on medium until creamed. Add the sugar and beat on medium for 1 minute until fluffy and becomes a paler yellow.
Eggs and vanilla – Add the eggs one at a time, mixing well after each addition. Beat in the vanilla extract.
Add the flour mixture into the bowl and beat on low until you can no longer see dry flour, then stop beating. You don't want to overmix.
Apples – Stir through the diced apples using a spatula. The batter will be quite thick, it's not pourable.
Bake – Spread the batter evenly into the prepared cake pan. Bake for 35 minutes, or until a skewer inserted in the centre comes out clean (because the batter is quite thick and if your oven runs a bit cool, it could take up to 45 minutes). (Note 3)
Rest and serve – Let the cake rest for 5 minutes in the pan before removing. Cool for a further 10 minutes then serve warm or let it cool completely on a wire rack. Dust with icing sugar, if desired. If serving warm, it's especially lovely with a scoop of ice cream.