Wash the basmati rice until the water runs clear. Soak the rice for 30 minutes, then drain and set aside.
Grind the cumin seeds, green cardamom, black cardamom, cloves, and cinnamon into a fine spice powder.
Heat oil in a large heavy-bottomed pot over medium-high heat. Add the sliced onions with a pinch of salt and sauté until golden and crisp, about 15 minutes. Remove the onions and set aside.
Add the lamb to the pot and sear on both sides for about 5 minutes.
Return the onions to the pot and stir in the grated garlic. Cook until fragrant.
Add 2 teaspoons of the ground spice mixture, salt, black pepper, and water. Bring to a boil, then reduce heat and simmer until the lamb is fork-tender, about 1 to 1 1/2 hours.
While the lamb cooks, prepare the toppings. Toast the almonds in a little oil until lightly golden. Set aside.
Cook the soaked raisins until plump and transfer them to a plate.
Sauté the shredded carrots until tender-crisp.
For the caramel sauce, heat 2 tablespoons sugar in a skillet until caramelized. Carefully add 1/4 cup water and stir until dissolved into a caramel liquid.
Remove the cooked lamb from the pot and measure the stock. Return 3 cups of stock to the pot and adjust salt so the broth tastes slightly salty.
Add the drained rice to the stock and bring to a boil.
Reduce the heat, place the lamb on top of the rice, sprinkle the remaining spice mixture over the rice, cover, and simmer until the liquid is mostly absorbed, about 10 minutes.
Drizzle the caramel sauce over the rice and add most of the carrots and raisins.
Cover and cook for another 5 to 10 minutes until the rice is fluffy and fully cooked.
Let the Kabuli Pulao rest for a few minutes before fluffing with a fork.
Garnish with the remaining carrots, raisins, toasted almonds, and optional ghee before serving.