Our Best-Ever Carrot Cake

Name: Our Best-Ever Carrot Cake
Prep time: 40 min
Cook time: 1 h 15 min
Total time: 1 h 55 min
Cuisine: American
Ingredients: 225 mL sunflower oil, plus extra to grease; 225 g light muscovado sugar; 4 medium eggs; 225 g self-raising flour; 1 tsp. bicarbonate of soda; 1 1/2 tsp. each mixed spice, ground cinnamon and ground ginger; 150 g sultanas; 200 g carrots, coarsely grated; 50-75 g walnuts or pecans, roughly chopped; 175 g unsalted butter, very soft; 1 tsp. vanilla extract; 275 g full-fat cream cheese, at room temperature; 200 g icing sugar; carrot decorations, optional, available from larger Sainsbury's stores (£1.50 for 12)