Mix the milk, eggs, cinnamon, sugar and vanilla in a bowl until well blended. Place Cinnabon bread on a shallow baking pan leaving room between each slice of bread. You are going to pour half of the entire mixture on the 6 slices of bread making sure that it soaks through the bread completely. Carefully flip each slice of bread and pour the remaining mixture on all 6 slices.
The tricky part here is making sure to pour off any excess mixture. Just make sure each slice has absorbed the mixture and then drain the remaining mixture. I usually save the remaining mixture in case I want to make a slice or two during the week.
Cover the bread with foil and put into the refrigerator overnight. The next morning, heat up your griddle and melt a little butter on the entire surface. You'll want to cook each slice of bread on both sides over medium to medium-high heat until brown and done.
Serve with your favorite syrup and berries. Enjoy!