In a pan, boil 3–4 cups of water. Add 2 cups of green peas and boil on a high flame for 5 minutes, until the peas become soft.
Strain the water from the green peas and transfer them to a mixing bowl.
While the peas are still slightly hot, mash them coarsely using a bowl or a masher.
Then add 1 cup sliced onion, 1 tbsp green chilli paste, 1 tsp grated ginger, salt to taste, ¼ tsp turmeric powder, 1 tsp red chilli powder, 1 tsp coriander powder, 1 tsp cumin powder, 1 tsp ajwain, a pinch of hing, 1 tsp dry mango powder, ½ tsp sugar, and 2 tbsp white sesame seeds. Mix well.
Gradually add 1 cup gram flour and bind the vada mixture.
Add 1 tsp oil and smooth the dough. Make medium-sized dough balls from the mixture.
Take a plastic sheet and grease it with oil. Place a dough ball on it and flatten it into a thin vada using your hand. Prepare all the vadas in the same way.
Heat oil and add the vadas to the hot oil. Fry on a medium flame until they become crispy and golden brown on both sides.
Serve hot matar vada with chutney and tomato ketchup.