Spicy seasoning paste for cooking or canning chipotles. From Rick Bayless, Frontera Grill in Chicago. This recipe can be half anchos and half guajillos or all chipotle, any combination of dried chiles to taste. Straining is a matter of personal preference. For cooking I don't usually bother with it, as long as the puree is very fine. For canning, I do work the recipe through one of those old-fashioned v-shaped food mills with the wooden pestle. I recommend any of Rick Bayless' books for more in-depth instructions on regional Mexican techniques.