Make the filling: Add the raspberries, blackberries, black raspberry liqueur, and 1 tablespoon of maple syrup to a large bowl. Stir and let sit for 10 minutes for the berries to macerate.
2. Step
In a medium bowl, mix together the cream cheese and remaining tablespoon of maple syrup until smooth.
3. Step
Spread the filling evenly over the 4 slices of bread. Arrange some of the berries on 2 slices of the bread and top with the other slices of bread. Press to seal the pieces together.
4. Step
In a shallow dish, whisk together the milk, egg, black raspberry liqueur, and salt.
5. Step
Melt the butter on a griddle or in a large skillet over medium heat. Quickly dip both sides of the bread pockets in the milk mixture, then transfer to the pan and fry on each side for about 3 minutes, until golden brown.
6. Step
In a large bowl, beat the heavy cream until soft peaks form. Add the maple syrup and continue beating until the cream holds medium peaks.
7. Step
Serve the stuffed French toast with a dollop of maple whipped cream and a scoop of macerated berries with their soaking liquid.
