Poriyal is just a term for vegetables that are cooked and seasoned. The method is the same for most of the vegetables. You can make this with beans (chopped fine), carrot(grated) and cabbage(shredded) or even a mix of beans, carrots and cabbage (this blend will b easy when making for a big group).
For Seasoning the ingredients are the same for all :-
Cooking oil - 1/2 tsp
Coconut oil - 2 to 3 drops (optional) - it gives great aroma
Mustard seeds - 1/4 tsp
Urad dhal - 1/2 tsp
Curry leaves - a few
Vegetable of choice
Green chilies - as per spice required
Salt to taste
In a deep dish pour oil and add the mustard seeds, urad dhal and the curry leaves. Now add chopped green chilies and the vegetable of choice. When the vegetable is 3/4 done add salt. Cabbage and carrot will cook fast and it doesn't need water to cook. Beans takes a little longer so just sprinkle water and cook the vegetables on low to medium heat and do not cover with lid.