I love cinnamon french toast, but I hate how the cinnamon clumps in the egg batter. I've tried various solutions (btw, adding it to the milk and stirring it up just makes cinnamon-milk foam) but this is the one that actually works.
1/2 cup cinnamon-sugar mix (nice and blended)
1 tsp vanilla
1/4 cup milk
16 slices bread
The only thing I actually measure are the eggs :P. Put the cinnamon-sugar in the dipping bowl. Add the eggs and the milk and the vanilla. Let sit for a couple minutes while the egg/milk soaks into the sugar. Mix well. Dip the bread as usual. Stir the eggs every time they sit for more than a minute or so, or the sugar accumulates on the bottom.