First, prepare the guacamole. To do so, peel and finely chop the tomato and spring onion, and add them to a bowl.
Open the avocado, removing the stone. Remove the flesh with a spoon, chop it and add it to the mixture. Add a tablespoon of oil, lime juice, salt, chopped cilantro to taste and a pinch of chili pepper, and the cooked prawns. Mix all the ingredients.
Next cook, the corn tortillas in a pan. Place a piece of cheese on the tortilla, allowing it to melt, and remove.
Put the tortillas on a plate and fill with guacamole, folding in half to make them easier to eat.