In a medium-sized mixing bowl, vigorously whisk the eggs, milk, cinnamon, and vanilla extract until thoroughly combined. In a separate small bowl, gently fold the chopped pecans into the whipped cream cheese until evenly incorporated. Evenly distribute the cream cheese mixture over six slices of brioche bread, then cap each with another slice to craft sandwiches enclosing the filling. Warm a griddle or frying pan over medium heat and melt the butter in batches if required. Immerse each sandwich fully in the egg mixture, ensuring both sides absorb the custard for 15–30 seconds. Transfer to the heated pan and cook in batches, browning each side until golden and crisp, about 3–4 minutes per side. Serve immediately, garnished with additional pecans, fresh banana slices if desired, and a drizzle of maple syrup.