Char tomatoes, chiles, garlic, onion, and jalapeños over high heat—broiler, gas flame, or hot cast iron—until tender and blackened in spots. Be gentle with the garlic to avoid bitterness.

In a molcajete: begin with garlic and onion, then add chiles and grind in circular motion; finish with tomatoes and salt to taste.

In a blender: add all roasted veggies, pulse gradually until chunky. Add salt and blend to desired consistency, thinning with water if needed.