To begin, soak the caterpillars in cold water and set aside.
Peel and chop the onions, peppers, garlic and tomatoes.
In a wok or frying pan, heat the oil and fry the onions over a low heat. Add the peppers, garlic and seasoning and stir.
Drain the caterpillars and discard any unwanted pieces and pat dry. Then add the caterpillars to the pan and mix well.
Fry over a medium heat for 10 minutes. When slightly crisp, add the tomatoes and cook for a further 10 minutes.
The caterpillars should be soft but with a crunchy texture. Add a knob of butter just before serving.