Place rice in large container and cover with several inches of cool water; let soak for 20 minutes. Drain.
Heat oil in a pressure cooker over medium heat. Add onion, cumin seeds, and bay leaves; cook and stir until onion is translucent, about 5 minutes. Stir in potatoes and carrots; cook until lightly browned, about 5 minutes. Stir in turmeric, chile powder, and coriander; cook until fragrant, about 1 minute.
Stir rice gently into the pressure cooker until evenly coated with oil. Pour in water and peas. Stir in salt, butter, and garam masala. Seal cooker and bring to high pressure according to manufacturer's instructions. Cook for 5 minutes. Remove from heat.
Release pressure naturally according to manufacturer's instructions. Fluff rice with a fork.