Give the Serranos a good rinse and de-stem them. Be sure to wash your hands after handling them. More tips on handling hot chiles.
Saute a roughly chopped ¼ onion and 1 whole, peeled garlic clove in a glug of oil over medium heat.
Once the onion is browning you can add 1 teaspoon Mexican oregano, some freshly cracked black pepper, and ¼ teaspoon cumin (optional). Briefly cook until fragrant and then add the de-stemmed Serranos, ½ cup white vinegar, ¼ cup water, and ½ teaspoon salt. You can optionally add a rinsed and de-stemmed Habanero pepper. Bring to a simmer and then add everything to a blender.
Add 8-10 sprigs cilantro and the juice of 1 lime to the blender. Combine well or to your desired consistency. I usually leave it a bit chunky but you can always blend it thinner.
Add mixture to two 5 oz. bottles or a small Mason jar. Store in the fridge where it will keep for weeks at a time.
