Marinate the whole chicken: Prick the chicken all over with a fork — these tiny holes help the yogurt marinade reach deep into the meat. Whisk together the yogurt, ginger garlic paste, lemon juice, Kashmiri red chili powder, turmeric, garam masala, and salt. Rub the marinade all over the chicken, inside and out, working it into every crevice. Cover and refrigerate for at least 4 hours, or overnight (up to 12 hours) for the deepest flavor.
Stuff with boiled eggs and truss: Take the chicken out of the fridge and let it sit at room temperature for 20–30 minutes (no longer, for food safety). Tuck the 3 peeled boiled eggs snugly into the cavity. Tie the legs together with kitchen twine and tuck the wing tips under the body so the bird holds a neat, compact shape — this is what gives musallam its signature regal look.
Sear for royal color: Heat the 2 tablespoons of ghee in a large, heavy-bottomed pot or Dutch oven over medium-high heat. Carefully lower in the stuffed chicken and sear for 3–4 minutes per side, turning gently, until deep golden all over — about 12–15 minutes total. This sear builds the burnished color and a base of flavor. Lift the chicken out and set aside.
Build the almond-cashew gravy: In the same pot, add the 3 tablespoons of ghee over medium heat. Toss in the cardamom, cloves, cinnamon, and bay leaf; sizzle 30 seconds until fragrant. Add the sliced onions and cook 10–12 minutes, stirring often, until soft and deep golden-brown. Stir in the ginger garlic paste and cook 1 minute. Add the chopped tomatoes and cook 5 minutes until they soften and melt into the onions. Now stir in the almond-cashew paste, Kashmiri red chili powder, turmeric, garam masala, and salt; cook 3–4 minutes, stirring, until the ghee begins to separate at the edges. Pour in the 1½ cups of water and bring to a boil.
Braise the chicken in the gravy: Lower the heat to a gentle simmer. Nestle the seared chicken breast-side up into the gravy and spoon some gravy over the top. Cover with a tight lid and simmer on low for 40–45 minutes, carefully turning the chicken once halfway through, until the juices run clear and the thickest part of the thigh reads 165°F / 74°C on an instant-read thermometer. If the gravy gets too thick, splash in ¼ cup of hot water.
Finish with saffron and cream: Stir the saffron milk and heavy cream into the gravy around the chicken (pour around it, not over the skin, so the burnished color stays). Simmer uncovered for 8–10 minutes until the gravy thickens enough to coat the back of a spoon. Let the chicken rest in the pot for 10 minutes, then transfer to a serving platter. Spoon the rich gravy generously over and around it, and garnish with toasted sliced almonds, fresh coriander, and ginger juliennes. Carve at the table — the golden boiled eggs inside make every slice a reveal.