Any dry rub recipe will work just fine, whether it is your own or purchased from the store. It is also important to cut the pork shoulder into a couple of smaller pieces, or slabs, prior to coating with the dry rub mixture. The dry rub can be placed on the meat a day in advance if desired, but at least 2 hours is necessary.
Place the pork shoulder pieces on the solid convection steam oven pan or a large plate. Season liberally with the preferred dry rub. Cover with plastic wrap and place in the refrigerator overnight or for at least 2 hours. Remove from the refrigerator and place the pieces of pork shoulder onto the wire rack, evenly spaced. Place the wire rack with the meat into the convection steam oven on rack position 2 and place the solid oven pan on rack position 1. Make sure to cover the solid pan with parchment paper. Turn the convection steam oven on by selecting the Convection Steam Mode set to 130°C. Set the timer for 1 hour, 30 minutes. After 1 hour and 30 minutes, check the pork shoulder to see if it is tender; if it is, remove and allow to cool slightly before serving. If continued cooking is needed, return the pork shoulder to the oven and cook for an additional 15 minutes or until tender.