Melt 2 tablespoons butter over medium-high heat in a large Dutch oven or heavy-bottomed soup pot.
Add the chicken, season it with salt and pepper, and brown it for about 2 minutes on each side.
Remove the chicken from the pot and set aside.
Add the rest of the butter to the pot along with the chopped onion, celery, carrots, and apple.
Season with sea salt and sauté for 2 to 3 minutes or until the onions are translucent.
Stir in the garlic, turmeric, curry powder, cumin, ground ginger, and cardamom; sauté for about 20 more seconds.
Add the tomato paste and stir until evenly distributed.
Stir in the red lentils, chickpeas, coconut milk, and chicken stock.
Return the chicken to the pot and bring everything to a boil.
Reduce heat to low, cover, and simmer for 20 minutes.
Remove the chicken from the pot and transfer it to a cutting board; chop it into bite-sized pieces and return it to the soup pot.
Give the stew a taste and, if desired, season with more salt and pepper.
Ladle into bowls and garnish with chopped fresh cilantro.