Mix pepper, mustard, salt, paprika and lemon zest. Squeeze and add the garlic and stir everything together with the oil (1) to a paste. Coat the meat all over with it.
Cut the peppers into quarters and remove the seeds. Put them on the bottom of an ovenproof dish. Remove the skin from the shallots, cut them in half and add them. Drizzle everything with olive oil (2). Put the marinated roast on top.
Meanwhile, roast the veal shoulder in the oven heated to 200 °C on the second rack from the bottom for twenty minutes, turning the roast once to the other side.
When it has browned, turn the oven temperature down to 160 °C and cover the roast with aluminum foil or a lid. Meanwhile, roast everything in the 160 °C oven for another hour and a half.
To serve, cut the veal shoulder into fine slices and bring to the table with the peperonata.