Prepare the eggnog mixture:
In a medium size bowl, using a hand mixer, beat together, the egg yolks and sugar until thick.
In a small saucepan, over low heat, combine the milk, cinnamon, nutmeg, and salt whisking constantly until warm.
Slowly, add about a fourth of the milk mixture into the egg yolk, whisking to combine. Pour this mixture back into the saucepan and cook until it starts to thicken, but does not boil. Whisk constantly.
Place the heavy cream in a bowl. Strain the egg mixture into the cream. Add vanilla and whisk to combine well. Chill for 1-4 hours.
This mixture can be made the night before, but use within 24 hours.
Prepare the French Toast:
In a large oval shaped or rectangle dish, whisk together the eggs, milk, cinnamon, vanilla, and the eggnog mixture.
Melt 2 Tablespoons of butter, over medium heat, on a griddle pan or skillet. Place 2 slices of bread in mixture at a time. Soak about 10 seconds on each side, allow excess to drip off. Place on hot griddle.
Cook over low-medium heat until light golden brown on each side, about 3-5 minutes each side.
Remove from griddle to serving plate. Sprinkle with confectioner sugar. May top with additional butter, pecans, berries, syrup or whipped topping.