01 - In a small mixing bowl, beat the softened cream cheese, granulated sugar, and vanilla extract together until completely smooth and creamy. Gently fold in the fresh blueberries, taking care not to crush them.
02 - Lay out 4 slices of brioche on a clean work surface. Divide the cheesecake filling evenly among them, spreading a generous layer on each. 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 no streaks remain.
04 - Dip each stuffed sandwich into the egg custard, letting it soak for about 15 seconds per side. Ensure both sides are evenly coated but not oversaturated.
05 - Melt the butter in a large nonstick skillet or griddle set over medium heat. Working in batches if needed, cook each sandwich for 3 to 4 minutes per side until deeply golden brown and heated through. The filling should be warm and the exterior crisp.
06 - Transfer the cooked French toast to serving plates. Dust generously with powdered sugar and finish with fresh blueberries, a drizzle of warm maple syrup, or a dollop of whipped cream as desired.