Heat oven to 325° F. Coat an 8 x 8 x 2-inch baking pan with nonstick cooking spray.
In a large bowl, beat butter and sugar together until smooth. Next, beat in egg and vanilla extract. On low speed, add in flour, 1 cup of the white chocolate chips, the dried cranberries and salt. Press evenly into bottom of prepared baking pan.
Bake at 325° F for 40 minutes or until center is firm to the touch. Cool completely on a wire rack.
Place the remaining 1/4 cup white chocolate chips in a small glass bowl. Microwave for 45 seconds. Stir until smooth. Transfer to a small resealable plastic bag. Repeat with the semisweet chocolate chips. Snip off a corner of each bag and drizzle chocolates over blondies. Cut into 16 squares, then cut each square in half, for a total of 32 bars.