- In a small saucepan, combine the milk, half and half, vanilla, cinnamon, whiskey, and rum. Bring the mixture to a simmer over medium heat.
- In a separate bowl, whisk together salt, sugar, egg yolks, and egg. Whisk this mixture pretty vigorously for about 5 minutes, or until the egg yolks have lightened a bit in color.
- Remove your milk mixture from the heat and temper it into your egg mixture by whisking it a a little at a time into the eggs, until you’ve added about half of the milk mixture. Add the remainder of the hot liquid and whisk until combined.
- Return the egg and milk mixture to your saucepan and put it back on the stove over low heat. Heat it, stirring frequently, until it has thickened a bit and will coat the back of a spoon, about 4 minutes. Remove the custard from the heat.
- Dip the challah slices into the custard and soak for about 30 seconds on each side. When the slices have been evenly coated with the custard, place them on a preheated skillet and cook for 3-4 minutes on each side, until golden brown.
- Serve hot and top with blackberry rum sauce and a sprinkling of powdered sugar.