Prepare your tins and preheat the oven. Set your oven to 180°C (160°C fan). Grease two 20cm round cake tins and line the bases with baking parchment. The smell of warm butter and paper should be the first cue you notice.

Whisk the dry ingredients. In a large bowl, sift together the flour, baking powder, bicarbonate of soda, cinnamon, nutmeg and salt. The mixture should look pale and uniform, with no lumps visible.

Combine the wet ingredients. In a separate bowl, whisk the brown sugar, caster sugar and eggs until thick and pale, about 2 minutes. The mixture should feel light and airy, and you’ll hear it change sound as it becomes frothy.

Add the oil, buttermilk and vanilla. Pour in the oil in a steady stream while whisking, then add the buttermilk and vanilla. The batter will become glossy and smooth, with a rich golden hue.

Fold in the carrots and walnuts. Tip the wet mixture into the dry ingredients and fold gently with a spatula until just combined. Scatter in the grated carrot and walnuts, folding until you see flecks of orange and brown throughout the batter. Be careful not to overmix — the batter should look slightly craggy, not like a smooth paste.

Bake the cakes. Divide the batter evenly between the two tins. Bake for 45–50 minutes. The cakes are ready when a skewer inserted into the centre comes out clean, and the tops are a deep golden brown. You should smell a warm, spiced aroma filling your kitchen. Let them cool in the tins for 10 minutes, then turn out onto wire racks to cool completely.

Make the cream cheese frosting. Beat the softened butter and cream cheese together until smooth and fluffy — about 3 minutes. Gradually add the icing sugar, one spoonful at a time, beating well after each addition. Add the vanilla extract and beat for another minute until the frosting is silky and spreadable. It should hold a soft peak when you lift the beater.

Assemble and decorate. Place one cake layer on a serving plate and spread a generous layer of frosting on top. Place the second layer on top and cover the entire cake with a thin crumb coat. Chill for 30 minutes, then apply the final layer of frosting, creating decorative swirls with a palette knife. Finish with a sprinkle of chopped walnuts and a light dusting of cinnamon.