1) Preheat oven to 350°F. Grease bottom only of 13x9-inch pan with shortening or spray bottom with cooking spray; coat with flour. In large bowl, beat cake mix, drink mix (dry), water, eggs and strawberries with electric mixer on low speed 30 seconds. Beat on medium speed 2 minutes. Pour into pan.
2) Bake 30 to 35 minutes or until toothpick inserted into center comes out clean. Run knife around side of pan to loosen cake. Cool completely, about 1 hour.
3) In chilled large bowl, beat cream cheese and milk on low speed until smooth. Beat in whipping cream and powdered sugar on high speed, scraping bowl occasionally, until soft peaks form. Frost cake. Store covered in refrigerator.