Mix eggs, milk, Seasoning Mix and sugar in large bowl until well blended. Add bread; toss to coat.
Pour into 6-quart slow cooker sprayed with no stick cooking spray. Cover with clean cotton kitchen towel overhanging sides of slow cooker*; place lid on top.
*Covering the slow cooker with a towel helps prevent moisture buildup.
Cook 1 1/2 to 2 hours on HIGH or until top of French toast no longer looks wet. Serve warm with maple syrup, if desired.