Heat the oil in the pan and add mustard seeds to it, as soon as the mustard starts to crackle, add green chillies to it.
Immediately add onion and cook till it becomes light brown.
Now add tomatoes and mix well.
Add all the spices - such as salt, turmeric, red chilli, garam masala and black pepper. Allow these spices and tomatoes to cook.
Put all the vegetables in it and cover it with a lid for 3-4 minutes and cook on low heat.
Add the seviyan and water and allow the water to come to a boil on high heat, as soon as the water comes to a boil, slow the flame and stir the seviyan and cover it with a lid.
Let it cook till the vermicelli absorbs all the water, it will take about 7 to 8 minutes. Stir it every 2-3 minutes
Turn off the gas and take out in a serving plate and garnish with coriander leaves.