The electric blender will be sitting this one out.
I'll be making salsa the old-fashioned way.
First I roasted the cloves of garlic and slices of onion until they were slightly blackened.
Next I put three "serrano" chiles on the griddle and let them blister. (The recipe called for four "chiles de árbol", but I don't think that "serranos" are quite as hot.)
You can see the mess the onions and garlic left. I was glad I put foil on the griddle.
I cut the stems off the peppers, and ground them into the mixture. Next the tomatoes are blackened.
So here is the finished product.