Line a 6-cup glass bowl or a deep serving dish with a large piece of plastic wrap to cover the bottom and sides of the bowl. This will make it easy to unmold the pudding. Remove the crusts from the brioche and cut it into about 1-inch thick slices. Arrange the bread slices in the prepared bowl, cutting as necessary, to cover the bottom and sides. You should have some leftover slices.
In a heavy bottomed saucepan, over medium heat, combine the cherries, sugar, 1 3/4 bunches of fresh mint sprigs, water and pinch of salt and bring to a boil. Reduce the heat and simmer until the berries begin to soften and release their juices, about 20 minutes.
Spoon about half of the cherry mixture into the prepared bowl. Put a layer of brioche slices on top of the cherries and press down gently. Spoon more of the cherry mixture over the brioche layer. Reserve a little of the cherry liquid for the sauce. Look at the brioche slices at the bottom of the bowl they should be nicely colored with the liquid but not too saturated or too wet. Next, cover with the last layer of brioche slices and add more of the cherry mixture. If you run out of brioche slices, you can always use your crust trimmings.
Tightly wrap the whole pudding and bowl with plastic wrap and put a plate, smaller than the top of the bowl, on top of the pudding to weigh it down. Put a heavy weight on top of the plate to compress further, such as heavy canned goods or even an iron skillet. Refrigerate for 8 to 12 hours.
Simmer the reserved cherry liquid in a small saucepan over low heat. Reduce the liquid by half, then discard the mint sprigs, cool down and store in the refrigerator until ready to serve.
When ready to serve, whip the cream in a large bowl until soft peaks form, then add a teaspoon of the reduced cherry syrup. Whip to incorporate. Unmold the pudding onto a serving plate. Brush some of the syrup over the pudding to add a nice sheen. Cut into wedges and serve with dollops of the flavored whipped cream. Drizzle some of the syrup over each serving and a garnish a fresh mint sprig. You can even put a fresh cherry on top if you have the urge!