In a large bowl, add salt to the heavy cream and whip until firm. Add the ham and bechamel sauce to a food processor and blend until creamy. Transfer the ham mixture into a mixing bowl and fold in the whipped cream. Line small serving bowls with plastic wrap and transfer the mixture into the bowls and let rest in the refrigerator for approximately 1 hour. Place the mold upside down on a serving dish and lift away the bowl along with the plastic wrap. Garnish with pomegranate seeds on top and insert crackers around the mousse.
In a saucepan, heat up the milk, and bring to a gentle simmer. In another saucepan, melt the butter and immediately add the flour. Lower the heat, and mix until the butter has absorbed all the flour and is the consistency of thick dough. Make sure the butter-flour mixture does not burn or brown. Remove the saucepan from the heat, and whisk in a couple of ladles of heated milk into the butter-flour mixture. Whisk until the flour has absorbed all of the milk. Put the saucepan back on the burner over medium heat, and whisk in the remainder of the milk. Continue whisking until the sauce thickens and becomes a creamy velvety consistency.