In a medium saucepan bring 2 cups of water to a boil over medium heat and add the cinnamon, cardamom, ginger, peppercorns and cloves, simmering for 2 minutes. Add the tea bags, milk and sugar, stirring to combine. Remove from heat then cover the pot and let it steep for 10 minutes.
Strain tea into a large mixing bowl, discarding spices and tea bags. Let cool completely to room temperature.
For the French toast:
In the large bowl whisk in the eggs, egg yolks and vanilla extract into the chai.
Heat a large cast iron skillet or non-stick sauté pan over medium heat, add 1 tablespoon of the butter and allow to melt.
Working with one slice of bread at a time, soak the bread in the egg mixture, turning to coat both sides.
Add two slices of the bread and cook until golden brown on the bottom, about 2 minutes. Flip and cook until golden brown on the other side, about 2 minutes. Add an additional tablespoon of butter and repeat with the remaining slices of bread.
Top with whipped cream or maple syrup and serve immediately.