If rice is not already cooked, prepare according to package directions.Heat one tablespoon of olive oil in a large dutch oven on medium heat.Once oil is hot, add chopped mushrooms and cook until tender and golden in colour.Remove mushrooms from the pot and set aside.Heat remaining 1 tablespoon of oil. Add onion, red pepper and garlic. Cook until onions are soft and translucent.Add mushrooms back to the dutch oven along with chicken stock, chicken, lemongrass, fish sauce, Worcestershire sauce and salt.Bring mixture to a boil then lower to a simmer for 5 minutes.Reduce heat to low. Stir in the half and half and coconut milk. DO NOT boil after this step.Place lid on the dutch oven and allow to cook on low for an additional 5 minutes.In a small bowl, combine the Thai red curry paste, chill garlic sauce, tomato paste, water and cornstarch. Whisk to a smooth consistently.Add curry mixture to the soup and stir until soup is slightly thickened and fragrant.Add rice and cilantro to the pot and stir to combine. Heat for an additional 5 minutes before serving.Garnish with cilantro and serve with fresh buns or naan.