Preheat a nonstick griddle over medium heat or an electric griddle to 325 degrees.
In a mixing bowl, using a fork, combine Neufchatel Cheese and raspberry jam, stir until well combined and nearly smooth (it's ok if there are a few small lumps); set aside.
In a blender combine buttermilk, milk, eggs, flour, baking powder, cinnamon, nutmeg, salt, and vanilla. Blend on low speed for ten seconds. Pour mixture into a shallow bowl; set aside.
Pour crushed graham crackers or cornflakes into a separate shallow bowl; set aside.
Make a slit down the center of each slice of French bread, cutting about three-quarters of the way down (basically you're making a butterfly, the bread should be slit down the middle but still connected).
Spread one and a half tablespoons of the raspberry mixture on one side of the inside of each slice of bread where the slit was made, then very gently press bread together.
Butter preheated griddle and dip one side of filled bread into milk/egg mixture (giving it a few seconds to soak up mixture and being careful not to immerse the center filled with raspberry mixture), then flip and dip opposite side several seconds. Allow a bit of the excess to drip off, then dip and coat both sides in crushed graham crackers. Place coated slice on preheated buttered griddle and cook until golden brown (about two to three minutes), then lift French toast with a spatula, butter griddle again, and flip French toast. Cook opposite side until golden. Repeat process with remaining slices of bread.
Serve cooked French toast immediately along with vanilla cream syrup and optional sweetened whipped cream.
