1. Heat oven to 350°F. Grease and flour 13x9x2-inch baking pan. Prepare CRUMB TOPPING; set aside.
2. Beat butter, granulated sugar and brown sugar until well blended. Stir together flour, baking powder and cinnamon; beat into butter mixture. Gradually add milk, egg and vanilla, beating until thoroughly blended. Pour 1/2 batter into prepared pan; top with 1/2 CRUMB TOPPING. Gently spread remaining batter over topping. Sprinkle remaining topping over batter.
3. Bake 30 to 35 minutes or until wooden pick inserted into center comes out clean. Cool completely.
4. Prepare WHITE DRIZZLE; drizzle over cake. Makes 12 servings.
CRUMB TOPPING: Combine 2/3 cup packed light brown sugar, 1/2 cup all-purpose flour, 6 tablespoons firm butter or margarine, 1 cup HERSHEY'S Premier White Chips and 1/2 cup macadamia nut baking pieces in medium bowl. Mix until crumbly.
WHITE DRIZZLE: Beat together 3/4 cup powdered sugar, 2 to 3 teaspoons milk, 1 teaspoon softened butter and 1/4 teaspoon vanilla extract. If necessary, add additional milk 1/2 teaspoon at a time until of desired consistency.