Pasadena has its Indian restaurants in real life. A Wikia contributor researching for fanfic discovered one whose menu is eerily similar to a typical "Indian" eaterie in the United Kingdom, right down to menu items originated for the British consumer, which are distinguished by having never seen any part of the Indian subcontinent in their existence. Chicken Tikka Massala, for instance, which if you asked for it in India, Pakistan or Bangladesh, would get you only a blank puzzled stare. This originated in Birmingham or Glasgow (accounts vary) and was the result of a customer asking for something chicken-flavored in a mild tomato curry sauce, The Indian chef used a catering-size tin of tomato soup, added cream and spices, and the rest is culinary history. The Balti curry definitely originated in Birmingham, a city with a large Asian population. This involves marinating meat and spices in a bath of clarified butter ("ghee"). This cardiac-arrest-on-a-plate is served in a balti -literally, in Hindi a "bucket'' - with rice. Both have seemingly migrated to the USA, possibly with British-trained Indian chefs. Although the Sitar Indian Cuisine restaurant in Pasadena calls it a "butter curry".
And it does prepare Rajesh Koothrappali's one concession to his native cuisine - lobster tails in korma sauce. Korma is a very mild curry, shading into Thai or Malaysian food, based on coconut and almond.