Mix eggs, half and half, and vanilla in a bowl. Set aside.
6 egg, 2 cup half and half, 1 tsp vanilla extract
Spray a slow cooker crock with nonstick cooking spray.
Place half of the bread cubes into the bottom of the slow cooker. Sprinkle with half of the brown sugar and half of the cinnamon. Repeat with another layer of bread cubes, brown sugar, and cinnamon.
⅓ cup brown sugar, 2 tsp cinnamon, 8 cup bread
Pour egg mixture onto the bread in the crock. Gently press bread into the crock so that the bread makes contact with the liquid. Place the lid on the crock and refrigerate overnight.
The following day, heat the french toast for 2-3 hours on low. If the condensation on the lid begins to drip, crack the lid halfway to allow steam to escape and the french toast to get a bit crispy on top.
Serve with syrup, powdered sugar, and breakfast sausage.