Stir in the tomato paste and fry for 5 minutes, stirring constantly, until it darkens slightly. This step builds flavor.
Pour in the blended pepper mix. Add curry powder, thyme, bay leaves, salt, white pepper, and the bouillon cube. Stir well.
Bring the sauce to a boil, then reduce heat and simmer uncovered for 15 to 20 minutes, stirring occasionally, until the sauce has reduced and thickened significantly.
Rinse the parboiled rice thoroughly under cold water until the water runs clear. Drain well.
Add the rinsed rice to the reduced pepper sauce. Stir until every grain of rice is coated with the sauce.
Pour in the chicken or beef stock. The liquid should just cover the rice; add a little water if necessary, but avoid too much liquid. Stir once.
Cover the pot tightly with aluminum foil before placing the lid on top. This traps the steam needed for cooking.
Reduce the heat to the lowest setting. Let the rice steam for 25 to 35 minutes. Do not stir during this time.
After 25 minutes, check the rice. If it is still hard, add a tiny splash of water, cover tightly again, and continue steaming.
To achieve the smoky flavor, allow the bottom layer of rice to slightly scorch (burn lightly) for the last 5 minutes of cooking.
Once the rice is tender, turn off the heat. Remove the foil and bay leaves. Add the sliced onion on top of the rice, cover the pot, and let it sit for 10 minutes off the heat to finish steaming and absorb the onion flavor.
Fluff the rice with a fork before serving.
Notes
Use long-grain parboiled rice for the best texture; Basmati can also work but may require less liquid.
For a richer flavor, use homemade stock instead of water or store-bought stock.
If you do not want to scorch the bottom, you can achieve a smoky flavor by placing a metal rack between the pot and the heat source, or by briefly grilling the cooked rice in a shallow pan over high heat after it is mostly done.