Take a mixing bowl and Put 2 tablespoon of cornflour, plain flour, salt, pepper powder, and water and mix it to form a light batter without lumps.
Add the paneer cubes to this and mix well to coat. Now heat 2 tbsp oil in a pan and shallow fry the paneer pieces until they are light golden in colour. Drain them onto a kitchen towel to soak excess oil.
Now in the same pan, add one tablespoon oil and when it's warm add ginger and garlic paste. Saute until the raw smell goes off.
Now add cubed capsicum and onion, and cook for 3-4 mins until the they turn a bit soft and crunchy on same time. Add soy sauce, chilli sauce, vinegar, tomato ketchup, salt and black pepper. Mix it and sauté.
Take 1/4 cup of water and add 1 tablespoon of cornflour to it and make a thin paste. Gently pour this into the pan and cook for 3-4 minutes with sautéing in between.
Add the paneer pieces and sauté for 1 minute and then turn off the flame.
Garnish with slit chillies and serve hot.