Pure gold Christmas drip cake

Name: Pure gold Christmas drip cake
Prep time: 1 h
Cook time: 30 min
Total time: 1 h 30 min
Cuisine: European, British
Ingredients: 225ml vegetable oil , plus extra for the tin; 375g plain flour; 3 tsp baking powder; 1½ tsp bicarbonate of soda; 375g golden caster sugar; 1½ tsp mixed spice; ½ tsp fine salt; 300ml buttermilk; 1½ tsp vanilla extract; 3 large eggs; 5ml red food colouring gel , we used Dr Oetker (optional); 250g pack slightly salted butter , at room temperature; 900g icing sugar; 1 tsp vanilla extract; 500g tub full-fat soft cheese; edible gold spray (optional); 200g white chocolate , chopped or grated