Preheat the oven to 350°F
In a dutch oven, heat on medium/high heat and add 2 tablespoons of olive oil
Season the lamb with salt and pepper all over, then sear each side of the lamb until browned (3-4 minutes per side). Remove the lamb and set aside.
Lower the heat to medium and add the onions, carrots, celery, and garlic to the oil and lamb juices. Cook until softened, about 7 minutes.
Add the sun-dried tomatoes, aleppo powder, and sumac. Cook until fragrant, about 30 seconds. Then add the wine and juice, stirring to combine.
Once that begins to boil, add the lamb, then place the lid on top and bake for 3-4 hours, or until the lamb is very tender.
Remove the lamb and set aside to cool. Strain the solids from the liquid. The solids can be eaten or made into a purée if desired.
Place the Dutch oven back on the stove and heat on high. Reduce the liquid to roughly 25% of the original volume (10-15 minutes), then keep warm on low heat.
Shred or chop the lamb into bite sized pieces, then add to the reduced liquid, stir to combine and keep warm on the stove.