Begin by cutting off the stems of the arbol chiles and shaking out some of the seeds to adjust the heat level. Heat a dry skillet over medium heat and toast the chiles for 2-3 minutes until they release a fragrant aroma, stirring occasionally to prevent burning.

Once toasted, transfer the chiles to a saucepan and cover them completely with boiling water. Turn off the heat, allowing the chiles to soak for 15 minutes until they’re softened and plump.

While the chiles soak, heat 2 tablespoons of olive oil in a skillet over medium heat. Add the finely chopped white onion, sautéing for 3-4 minutes until translucent. Stir in the minced garlic and cook for another 1-2 minutes, then add the chopped Roma tomatoes and cook together for about 5 minutes.

In a blender, combine the sautéed onion mixture, softened chiles, fresh lime juice, and a pinch of salt. Blend until smooth, adding reserved soaking water if necessary to reach your desired consistency. Taste and adjust seasoning as needed.