Make the chicken broth. Heat oil in a large pot over medium heat. Add the fried shallots, garlic, ginger, cumin, and turmeric, and saute for 1 minute or until aromatic.
Add the chicken thighs, chicken broth, lime leaves, chili de arbol, lemongrass, and black pepper to the pot. Cover and bring to a boil. Reduce heat to low and continue to simmer for 30 minutes or until the chicken is tender. Discard the lime leaves, lemongrass, and chili de arbol. Remove the chicken and shred the meat.
Meanwhile, make the garlic chips. Heat ¼ cup in a small saute pan over medium heat. Add the sliced garlic and cook until lightly golden brown. Remove from heat and let cool completely. The garlic will continue to cook in the hot oil. Once browned, remove garlic with a slotted spoon and drain excess oil on paper towels. Set aside.
Add shredded chicken back to the soup and season with fish sauce, coconut milk, and salt. Add the shredded cabbage to the soup and cook until tender, about 2 minutes.
Cook the noodles and portion them into 4 bowls. Ladle the soup on top along with the poached eggs, fresh scallions, and cilantro. Garnish the bowls with the fried garlic chips, drizzling the garlic oil on top. Serve with lime wedges on the side if desired.