1Heat oven to 350°F. Spray cookie sheets with nonstick cooking spray or line with parchment paper. In a large bowl, beat butter, sugar, brown sugar and orange zest on medium speed of the electric mixer until well blended. (The mixture will have the consistency of wet sand.) Add the egg and vanilla and beat until smooth.
2In a small bowl, stir together the flour, baking powder, baking soda and salt. Add to the sugar mixture and stir by hand until almost combined; add the cranberries and white chocolate and stir just until blended.
3Drop spoonfuls of dough about 1 inch apart on a cookie sheets. Bake 12 to 14 minutes, until light golden and set around the edges but still soft in the middle. Let set on cookie sheet 1 to 2 minutes. Transfer to a wire rack to cool.