These mini apple and cinnamon french toast casseroles are simple to make, but they'll need to sit overnight so plan ahead![br] As these bake, they'll puff up like souffles (a good inch or two over the edge of the pan) but they'll settle back into themselves as they cool.
In a large bowl, whisk together the eggs, milk, 2 tablespoons maple syrup, vanilla, cinnamon, nutmeg, cardamom, and salt until light and frothy. Add the bread pieces and apple; toss several times to coat well. Cover and refrigerate overnight.
Heat oven to 350*F. Butter 9 muffin cups. Give the bread mixture a good stir to incorporate any liquid that has settled, then divide between the prepared cups.
In a small bowl, mix together brown sugar and 2 tablespoons maple syrup until it resembles wet sand. Drizzle over the top of the muffin cups. Bake for 20 minutes, or until puffy and golden brown.
To release, run a knife around the outside of each muffin cup. Gently pry the casseroles out with a spoon.