The term pastelitos simply means "little pies". There are many versions which vary with the country or region in which they are made. The dough is sometimes quite simple; a variation of pie dough while other versions use a more complex puff pastry.
In New Mexico the dough is typically a simple flour, salt, baking powder and shortening mixture. The treats are made in large flat pans and cut into rectangles. Common fillings include raisins, prunes, and dried apples. The filling is cooked down to a thick paste then spread on a bottom layer of dough then topped with another layer of dough.
This simple dessert is made for special occasions and is a fall harvest tradition.
You can find recipes for savory pastelitos as well with fillings of meats and vegetables. These tend to be more like small turnovers. Here are some recipe links.
This recipe makes about 20 servings and freezes well.