Line 13- x 9-inch metal cake pan with parchment paper; set aside.
In saucepan over low heat, melt butter with white chocolate, stirring occasionally, until smooth. Let cool for 10 minutes.
Using wooden spoon, stir in sugar, then eggs, 1 at a time, stirring well after each addition. Stir in flour, cranberries, orange rind, vanilla and salt. Spread in prepared pan. Bake in centre of 325°F oven until cake tester inserted in centre comes out clean, 30 to 35 minutes.