Puttu: It is a very popular food in Thiruvananthapuram and throughout Kerala. It is a traditional breakfast dish made with rice flour and coconut that is steamed in a cylindrical bamboo or metal mould. The resulting cylindrical-shaped cake is then served with a variety of accompaniments, such as kadala curry (black chickpea curry), vegetable stew, or ripe bananas. 

In Thiruvananthapuram, you can find Puttu being served in many local restaurants and street food stalls. It is also a popular home-cooked breakfast item. In fact, Puttu is so popular in Kerala that there are even dedicated Puttu shops that sell a variety of Puttu dishes, including those made with different grains, such as ragi, wheat, and corn. 

Appam: It is a type of pancake made from fermented rice batter and coconut milk. The dish is usually served with vegetable stew, chicken curry, or fish curry. 

Appam is a staple breakfast food in Thiruvananthapuram and is commonly found in local restaurants and food stalls. The dish is also a popular choice for special occasions such as weddings and festivals. Appam is known for its unique taste and soft texture, which is achieved by fermenting the rice batter overnight. 

Idiyappam: Idiyappam,also known as string hoppers, is another popular food in Thiruvananthapuram, the capital city of the Indian state of Kerala. Idiyappam is made from rice flour that is pressed into thin, noodle-like strands and then steamed. 

Idiyappam is a versatile dish and can be served with a variety of curries, gravies, and chutneys. In Thiruvananthapuram, it is commonly paired with vegetable stew, chicken curry, or fish curry. The dish is also a popular breakfast food and is often eaten with coconut chutney or sugar and grated coconut. 

Idli: It  is not a traditional food of Thiruvananthapuram, which is located in the state of Kerala in South India. In Kerala, the most popular breakfast food is appam or puttu, which are rice-based dishes. 

However, idli has become a popular food item in Thiruvananthapuram in recent years, likely due to its popularity in other parts of India and its ease of preparation. Many restaurants and street vendors in the city now offer idlis, which are typically served with coconut chutney and sambar. 

Additionally, Thiruvananthapuram is a cosmopolitan city, with people from all over India and the world living there. As a result, there is a wide variety of food available in the city, including idlis, which are enjoyed by both locals and visitors alike.