Cook the lentils in a small pot according to instructions - cook until a little harder than al dente (they'll finish cooking in the stew)
In a large stock pot or sauce pot over medium-high heat, combine onions, garlic, and ginger with 1 tbsp oil. Sautee until onions are translucent; 5-6 minutes.
Add cooked chicken and tomato paste; mix thoroughly and saute another 2-3 minutes.
Add chicken broth, coriander, turmeric, and garam masala. Taste broth and add salt if necessary.
Reduce heat to medium-low, cover, and simmer for 30-40 minutes.
Add al dente lentils and simmer for another 15 minutes.
Finally, add chopped dried plums and simmer for 10 minutes more.
Serve with steamed basmati rice or naan bread.