1Heat oven to 350°F. Spray cookie sheet with cooking spray. Make cake and cookie mix as directed on box for gingersnaps, using 1/4 cup flour, 2 tablespoons butter and 1/4 cup water. Stir in ginger. Divide dough in half. Shape each half into 11x5-inch rectangle on cookie sheet.
2Bake 30 minutes or until light golden brown. Cool on cookie sheet 10 minutes. Cut crosswise into 1/2-inch slices. Turn slices cut sides down on cookie sheet.
3Bake about 15 minutes, turning once, until crisp and light brown. Immediately remove from cookie sheet to cooling rack. Cool completely.
4In small microwavable bowl, microwave white chocolate uncovered on High 1 minute to 1 minute 30 seconds, stirring once, until softened and chocolate can be stirred smooth. Dip one end of each cookie about halfway into white chocolate. Place on waxed paper until set.