Blend half-and-half, eggs, sugar, vanilla extract, and salt in a blender until smooth. Arrange bread in a 9x13-inch baking dish; sprinkle with raisins and cinnamon. Pour egg mixture over bread.
Place baking dish in a large roasting pan; fill roasting pan with boiling water halfway up the sides of the baking dish.
Bake in preheated oven until set, about 1 1/2 hours. Serve warm or cold.