Preheat the oven to 350F/177C and grease or line a standard-size loaf tin.
In a medium-size bowl, beat together the butter and sugar until light and fluffy.
Beat in the eggs, ground ginger, vanilla extract and salt until everything comes together.
Gently stir in the flour and baking powder.
Mix in the chopped cranberries and chopped white chocolate until evenly dispersed.
Spread the mixture out into the lined or greased loaf tin and bake in the preheated oven for 20 minutes, until golden brown and springy to the touch.
Leave the cake to cool in the loaf tin.