Whisk the cream, milk, eggs, vanilla and salt to combine.  Pour into a large baking dish and place the slices of bread in the custard to soak while you prepare the remaining ingredients.

For the Maple Butter: Combine the butter, maple syrup and salt and mix using a hand mixer until well mixed and homogenous.  Set aside until ready to serve.

For the Whipped Vanilla Bean Mascarpone: Combine the mascarpone cheese, heavy cream and sugar and beat with a hand mixer until fluffy, about 20 to 30 seconds.  Scrape the inside of the vanilla bean using the back of a knife and add to the mixture.  Beat again until the vanilla seeds run throughout the mixture, just a few seconds more.  Set aside until ready to serve.

Heat a large nonstick skillet over medium heat for at least 5 minutes.  Add 2 tablespoons of butter to the skillet for every four slices you cook and let melt.  Add the slices to the pan and cook on each side for 4 to 5 minutes, or until golden brown.  You may have to cook in two to three batches.  Keep warm in a 200° oven until all the toast is cooked.  Serve with a scoop of Maple Butter, Whipped Vanilla Bean Mascarpone and extra maple syrup, if desired.