Add the eggs to a large bowl and whisk until blended.
Mix in cinnamon and nutmeg.
Whisk in brown sugar.
Add in the milk, syrup, and vanilla extract and mix until well blended.
Butter a 13 x 9 inch casserole dish. Add the bread slices to the pan, being careful not to overlap.
Pour the egg mixture over the bread. Cover and refrigerate overnight.
Preheat oven to 350 degrees. Bake the casserole for approximately 45 minutes or until puffy and browned.
Serve with more syrup, cinnamon and powerded sugar.