Generously grease the inside of your slow cooker with oil.Cut the bread into 1-inch cubes, enough to make 5 cups, gently packed. Store leftover bread for another use. Put the cubed bread into the slow cooker. Sprinkle the raisins over the top.In a medium bowl, whisk together the eggs, milk, maple syrup, vanilla, and cinnamon until smooth.Pour the egg mixture over the bread cubes. Using a fork, press down firmly on the bread cubes to soak them in the liquid a bit. The bread will bob back to the surface.Secure the lid and dial the slow cooker to the high-heat setting. Cook for 2 to 2 1/2 hours, until the egg is firm on the top and the bread is lightly crusty around the edges. Serve with yogurt, fruit, and/or maple syrup.