Bring a large pot of salted water to a boil. Set up a bowl of ice water alongside. Add the broccoli to the pot and blanch for 1 to 2 minutes, just until bright green and crisp. With a slotted spoon, remove the broccoli to the ice water to shock. Drain well.
Place the pancetta in a medium skillet over medium heat. Cook, stirring often, until crispy and browned, about 10 minutes. Drain on paper towels, reserving 1 tablespoon of the fat.
Meanwhile, in a large bowl, use a rubber spatula to mix together the mascarpone, mayonnaise, cider vinegar and salt. Add the broccoli, pancetta, reserved fat, cranberries, walnuts and gorgonzola. Toss well to coat and combine.