1Heat oven to 350ºF (325ºF for dark or nonstick pan). Grease bottom only of 13x9-inch pan; lightly flour. In large bowl, beat cake ingredients with electric mixer on low speed 30 seconds, then on medium speed 2 minutes. Pour into pan.
2Bake 35 to 40 minutes or until toothpick inserted in center of cake comes out clean. Run knife around sides of pan to loosen cake. Cool completely, about 1 hour.
3In chilled large bowl, beat cream cheese and milk with electric mixer on low speed until smooth. Beat in whipping cream and powdered sugar on high speed, scraping bowl occasionally, until soft peaks form. Spread frosting over cake. Store covered in refrigerator.