Cinco de Mayo is my all-time favorite food holiday—there can never be enough Mexican or Tex-Mex in my life. Most Mexican cooking I know I learned from Rick Bayless's Mexican Everyday, which I've used so much that it's less a book than bunch of loose pages with a broken spine. Luckily, I have most of my favorite recipes memorized, like this incredibly red enchilada sauce.
It's the procedure that develops the deep and rich flavors of this sauce. It starts with toasting moderately spicy guajillo chilies, followed by pureeing them with garlic, tomatoes, cumin, and black pepper. The sauce is then strained into a saucepan with hot oil and cooked into a thick paste. This is the messy part—as the sauce reduces, it also wants to splatter everywhere. Constant stirring helps combat this, but doesn't alleviate it completely... you've been warned. Finally, chicken stock is added, the sauce is simmered, seasoned, and it's good to go.
The guajillos really define the sauce, giving it an earthy heat throughout, while the reduction step creates a very robust tomato base. Spread this sauce over chicken-stuffed corn tortillas, top with cheese, bake, and you'll be in enchilada heaven.