Heat a large stainless steel skillet over medium high heat, add pecans and toast until nuts are aromatic and beginning to brown, gently tossing the nut in the skillet while they toast, about 5 minutes. Remove from pan and when cool enough to handle coarsely chop.
Add bacon to skillet and return to medium heat. Cook, stirring frequently, until brown and crisp, about 12 minutes. transfer to a paper towel-lined plate to drain.
In a large bowl combine half and half, milk, maple syrup, eggs, and a pinch of salt and whisk to combine. Dip sliced bread in batter then arrange bread along bottom of an 8- by 11-inch baking dish. Scatter pecans and chopped bacon over the bread, then dip remaining bread in the batter and arrange on top. Re-whisk batter then pour remaining batter over the bread and press down gently. Let stuffed French toast sit in the fridge for an hour, or up to overnight.
When ready to bake preheat the oven to 375°F and bake until top of French toast is cooked though and tops are browned, about 25 minutes. Slice and serve hot with maple syrup.