In a 1 to 1 ½ quart shallow baking dish (eyeball it, and see if it looks big enough to hold the biscuits) combine the melted butter, pesto, salt and 2 tablespoons of the Parmesan.
Separate the dough into biscuits, and cut each biscuit into quarters. Place the pieces into the baking dish with the butter mixture and use your hands to toss to combine and coat the pieces well. Distribute the dough pieces out evenly in the dish. Sprinkle with the remaining 2 tablespoons Parmesan cheese. Cover with aluminum foil.
Bake for 20 minutes, then remove the foil. Bake for another 15 to 20 minutes until the top is golden brown and the inside is cooked through, with no doughy pockets (use a butter knife to check out the middle).
Cool for 5 to 10 minutes in the pan on a wire rack, then serve warm (either in the pan or removed to a serving plate) and let everyone pull it apart into hunks.
Notes
While some monkey breads are piled high in a deep baking dish, I find that spreading out the chunks of dough in a shallower pan gives you more appealing crusty bites, and also allows the bread to bake more evenly. You still want the biscuit chunks to be layered so you get the soft steamy inside, but this will allow the bread to cook more evenly, without a mushy pocket in the middle.