Cook carrots, french beans, potatoes, and green peas for about 12 minutes in a pressure cooker on medium heat.
Peel and chop the cooked carrots and potatoes when warm. Chop the french beans as well.
Now, mash the potatoes with a potato masher.
After the mashed potatoes have cooled, add chopped carrots, french beans and green peas. Set aside this mixture.
Preparing breadcrumbs
Cut about 8 slices of bread and add them to a mixer. Process for 30 seconds for coarse breadcrumbs.
Transfer it to a bowl and keep it aside.
Preparing mayonnaise dressing
Put the mayonnaise in a small mixing bowl and add crushed black pepper and mustard seeds to it.
Add lemon juice, vinegar, salt and sugar.
Whisk the dressing and keep it aside.
Preparing vegetable patty mixture
In a mortar and pestle, crush ginger, garlic, and green chillies.
Heat 1 tsp oil in a pan. For a few seconds, sauté the paste of ginger, garlic, and green chillies until the raw aroma of ginger and garlic is gone.
Add chopped onions and sauté till the onions turn translucent.
Add the spices - cumin powder, garam masala powder, red chilli powder, coriander powder and turmeric to the mix and stir well.
Switch off the gas and add chopped coriander leaves.
Add the sautéd mixture to mashed vegetables. Also, add breadcrumbs and salt and mix well.
Make the vegetable patties the same size as that of the burger buns. Keep these patties aside.
Preparing batter
Mix rice flour, gram flour, maize flour, and water in a medium mixing bowl.
Stir well and make a smooth batter without lumps. Keep aside the batter with medium consistency.
Pan-frying patties
Heat 4 tbsp oil in a pan for frying the patties.
Dip the patties in the batter and coat them evenly. Place the batter coated patties on breadcrumbs. Make sure to coat the patties thoroughly with breadcrumbs.
Now, place the patty on the heated pan.
Cook each patty until browned and heated through.
Once crisp and golden, place them on paper towels.
Assembling veggie burger
Slice the buns in half and spread some butter on the slices.
Heat a small pan and toast the buttered side till they turn crisp and golden.
Apply mayonnaise dressing to the crisp side.
Place the vegetable patty and top it up with sliced onions and tomatoes.
Again top up with mayonnaise dressing and sliced cheese.
Finally, add chopped lettuce and the burger bun.
Your veggie burger is ready to be served and eaten. You can always change the vegetables and dressings according to your choice.