Preheat oven to 350°F. Coat 8- or 10-cup baking dish with cooking spray.Whisk together eggs, milk, mustard, and nutmeg in large bowl. Season with salt and pepper, if desired. Add bread cubes, and press bread down into liquid to submerge. Set aside to soak while preparing vegetables.Heat 2 Tbs. reserved artichoke oil in skillet over medium heat. Add onion, and sprinkle with salt, if desired. Sauté 5 to 7 minutes, or until softened. Reduce heat to medium-low, and stir in artichoke hearts, 1 Tbs. thyme, and paprika. Sauté 5 to 7 minutes more, or until artichoke hearts are tender and beginning to brown.Stir artichoke mixture and Cheddar cheese into bread mixture. Transfer mixture to prepared baking dish, and sprinkle with Parmesan and remaining 1 Tbs. thyme. Bake 45 minutes, or until top is golden brown and custard is set.Related: How to Prep Artichokes