Beat first 3 ingredients at medium speed with an electric mixer until light and fluffy.
Cut ends from bread.
Cut bread into 6 slices; cut a pocket through top crust of each slice. Stuff each slice evenly with cream cheese mixture; place in a lightly greased 13- x 9-inch dish.
Whisk together eggs, half-and-half, and vanilla; pour mixture over bread slices. Cover and chill 30 minutes, turning once.
Cook bread slices on a lightly greased griddle over medium-high heat 3 minutes on all 4 sides or until golden.