Prepare the marinade. Dice your onion and toss into a Ziploc bag or other marinating container along with your boneless pork roast. Then add the following to a blender cup: the chipotle peppers in adobo, garlic cloves, olive oil, 1/2 cup of the 1 cup orange juice (save the other half for later), cumin, salt, pepper, cinnamon, and cilantro. Pulse the marinade ingredients in your blender a few times to mix, but it does not need to be perfectly smooth. Pour over the meat and onion in your marinating bag. Close the bag and squish it around to evenly coat everything. Refrigerate for 2 hours.
2-3 pound Boneless Pork Sirloin, 1/2 large Onion, 3.5 ounces Chipotle Peppers in Adobo, 5 cloves Fresh Garlic, 2 tablespoons Olive Oil, 1 cup Orange Juice, 1 teaspoon Cumin, 1 teaspoon Salt, 1 teaspoon Pepper, 1/8 teaspoon Cinnamon, 1 cup Cilantro (stems and leaves)
Preheat your smoker to 250 degrees. Take out a 9x13 pan. Rip off 2 sheets of aluminum foil a little longer than your pan. Lay them side by side, overlapping the edges by about an inch. Fold the edges over to create a seam that can trap the juices. Lay the foil in your 9x13 pan, then pour out your pork sirloin roast and the entire marinade into the pan on top of the foil. Insert your meat thermometer into the thickest part of your roast.
Place on your smoker and smoke until it reaches 160 degrees F, about 2 hours.
When the internal temperature of the meat reaches 160 degrees, take it off your smoker temporarily to add another 1/2 cup of orange juice around the roast. Slice an orange and lay the slices on top of the roast. Fold the sides of the foil up around the roast to seal it in, adding another small sheet on top if needed to completely wrap it. Place it back on the smoker until your pork roast reaches a temperature of 200-205 degrees f.--this took me 3 hours. If you want to speed it up, you can turn the temp up to 275 degrees F.
1 orange sliced
Once your pork roast reaches the desired temperature, remove it from the smoker and let it sit on the counter, still covered in foil, for at least 30 minutes. This resting period is really important to allow the juices to redistribute so that the meat is tender, not tough. It will be hard to wait, but it's worth it!
When the rest is finished, decide how you want to eat the roast and either slice the meat or pull it apart. Enjoy!