I love to make salsas using roasted ingredients. And it happens to be the way that many salsas are made in the Yucatan, where Pedro grew up. On the left I am using comales (cast iron griddles) to roast tomatillos, jalapenos, tomatoes, onions, garlic and habanero as the basis for two different salsas. You can't see all of the ingredients in the picture.
Then I made a Tomatillo Salsa (the green salsa) by blending the roasted tomatillos, garlic, jalapeno (seeded), onion and salt to taste. Vegan.
The other sauce is Salsa de Jitomate also known as Chiltomate. It has the roasted tomatoes, garlic, habanero (seeded) and onion, plus fresh cilantro and salt to taste. I blend them in the blender. Then the Jitomate Salsa is then fried on the stove in a bit of vegetable oil until the flavors become even more developed. Vegan.
Usually I just make salsas without a recipe, adding whatever I have on hand. But, as far as cookbooks go, I recommend the salsa recipes in Rick Bayless' cookbooks.