01 - In a small mixing bowl, beat the softened cream cheese, granulated sugar, and vanilla extract together until smooth and creamy. Gently fold in the fresh blueberries, taking care not to crush them.
02 - Lay out all 8 bread slices on a clean work surface. Divide the cheesecake filling evenly across 4 slices, spreading it in a generous, even layer. Place the remaining 4 slices on top to form 4 stuffed sandwiches, pressing gently to seal.
03 - In a wide, shallow dish, whisk together the eggs, whole milk, ground cinnamon, and salt until fully combined and smooth.
04 - Dip each stuffed sandwich into the egg custard, letting it soak for about 10 seconds per side. Ensure both sides are evenly coated but not oversaturated.
05 - Melt the butter in a large nonstick skillet over medium heat. Working in batches if needed, cook each sandwich for 3 to 4 minutes per side until deeply golden brown and the filling is warmed through.
06 - Transfer the cooked French toast to serving plates. Dust generously with powdered sugar and finish with additional fresh blueberries, a drizzle of maple syrup, or a dollop of whipped cream as desired.