Preheat the oven to 200°. Place bread slices on a baking sheet and toast until dried out, about 20 minutes, turning once.
In small saucepan over medium heat, combine the milk, cream, rosemary sprigs, onion and nutmeg. Bring to a simmer and remove from heat. Set aside to cool. Once the milk mixture is room temperature, strain out the rosemary and the onion. Place the eggs in a large bowl and whisk in the milk mixture, creating thick custard.
In a separate bowl, mix the ricotta, Parmesan, chopped rosemary and chives. Lightly grease a 2-1/2-quart baking dish. Spread an even layer of cheese mixture over each piece of bread and layer the bread in your baking dish so it slightly overlaps. Pour custard over bread, pressing down to make sure the bread absorbs the custard. Let it rest for 1 hour.
Preheat oven to 400°. Cover baking dish with aluminum foil and cook for 20 minutes. Remove foil and cook for another 30 minutes, until the top is golden brown, and when pressed, cream does not rise to the surface. Let cool for 10 minutes and serve.
Looking for groceries for this recipe? Miya shops locally at Native Sun Jax!