Place a baking sheet with a cooling rack on top of it into the oven.
Preheat oven to 200°F
In a large frying pan, melt the stick of butter over low heat.
While the butter is melting, add all ingredients except for the challah and the butter into the canister of a blender.
When the butter has melted, add it to the blender as well.
Return the pan to the stove and turn the heat up to medium.
Close the blender, and blender on medium speed until well combined. About 30 seconds.
Empty the contents of the blender into a high sided shallow dish Coat each side of the Challah with the blended mixture, one at a time. And immediately place into the frying pan. Add as many coated slices to the pan as you can, without crowding. In my 12in skillet, that means I can put in two at a time.
Cook each side until golden brown. About 3-5 minutes per side.
As each slice is cooked, remove from the frying pan and add it to the cooling rack inside the oven to keep it warm.
Continue coating the remaining slices in the mixture and cooking them until you run out of bread. Adding to the oven to keep warm.
Remove from the oven, and serve with your favorite toppings.