To start the salsa, first, peel and wash the tomatillos. Then place into a pot, along with the Serrano peppers, cover with cold water, and bring to a simmer.

In the meantime, peel and roughly chop the garlic. Then finely dice the onion and set aside, while you chop the cilantro.

Once the tomatillos. turn a golden yellow color and start to split, remove them from the water.

Note: If frying or grilling the tomatillos, onions, and garlic — toss with a bit of oil and then cook, turning often, until tender and charred, approximately 5–8 minutes. If grilling the vegetables, cut the onions into wedges and use half a head of garlic and then just squeeze it out once cooked.

To make the salsa, first, place the garlic into the blender. Cut off any stems from the serrano peppers and add to the blender. Once the tomatillos are cool enough to handle, remove any large cores. Do not remove these prior to cooking or they will become water-logged. Add the tomatillos and salt to the blender and pulse just a few times. If you still see big chunks of chilies, pulse a couple more times.

Pour into a bowl and add the onion and cilantro. Mix and taste for seasoning. Depending on the tartness of the tomatillos, you may want to add a squeeze of lime juice. At this point, this dish is called Salsa Verde.

To make this into Salsa Verde de Lupita, simply dice the avocado and gently fold it in.