Whisk eggs, milk, cinnamon, vanilla, and salt together in large bowl. Then whisk in 1/2 cup sweet potato until combined. Pour batter into a pie pan. Dunk each piece of bread into the batter, coating well. Place on sheet of parchment paper.
Melt butter on a griddle or in a large pan, spreading to cover the surface over medium heat. Add bread, pressing down lightly. Cook for 4 minutes until starting to brown, then flip and repeat. Cook until both sides are browned.
Mix 1 tablespoon of maple syrup with remaining half cup sweet potato. Spread thin coating on each slice of bread and stack. Top with bacon, maple syrup, and dollop of whipped cream, yogurt, or creme fraiche.