Marinate the chicken, sea food or par boiled vegetables with the ingredients mentioned for marination and keep aside for and hour.
In the meanwhile take a big pot with lots of water, add salt and bring it to a boil, as soon as it boils add the tomatoes and let it cook for 7 mins. Switch off gas and transfer the tomatoes in cold water, this will help to remove the skin
Once tomatoes are cold enough, remove skin, cut in cubes and transfer it to a mixie add chillies and basil leaves in it and puree it to make a smooth sauce.keep it aside.
Now take a pan and add oil, when hot add in garlic when it is soft add in the tomato sauce ketchup, salt, black pepper, chilli flakes, sugar and let it cook on medium flame till rawness of the tomato goes away.
You can add a little water to manage the consistency. It should be pouring consistency.
Meanwhile take a bowl add in maida , corn flour salt and black pepper mix it well then add in the soda water and mix it well add little by little, the consistency should be like pakoda batter consistency.
Do not beat it as we need the froth, do not panic if there are lumps. The lumps will give the tempura its crispy texture.
Keep a kadhai with oil for deep frying, when oil is hot lower the flame to medium dip the chicken or veggies in the batter and deep fry on medium heat till get a nice light pink colour.
Arrange the fried pieces on a plate and pour the tomato sauce on it garnish with basil fresh leaves or sprinkle dried basil and enjoy hot