For a fun party — lay out bowls of tortillas, fillings, salsas, beans and condiments and let people help themselves. You can use a colorful tablecloth and decorate the table with fresh chilies. The reason this is a great way to entertain is that people can choose the combinations they want in their tacos — for instance a vegetarian can make a taco with beans, cheese, and tomato salsa, a pork eater can make one with pork and tomatillo-avocado salsa, they don’t need to put it all on the same taco! A fun dessert for the Taco Party is Haagen-Dazs Dolce de Leche ice cream on sugar cones!
Rinse pork and put in a 6-qt. pan. Add onions, celery, garlic, bay leaves, thyme, salt, and enough water to cover meat — about 3 qts.
Bring this to a boil over high heat, cover, reduce heat, and simmer until meat is very tender when pierced with a fork, 2 to 2-1/2 hours. With slotted spoons, transfer pork to a 9 by 13 inch pan; reserve cooking juices. Discard string, and use 2 forks to pull meat into large chunks. Pour milk over meat.
Bake pork in a 325 degree oven until drippings are browned, about 1 hour, stirring and scraping pan occasionally.
Meanwhile, pour reserved juices through a strainer into a bowl; discard residue. Skim and discard fat. Return juices to pan. Boil over high heat until reduced to 2 cups, about 45 minutes.
When pork drippings are browned, add 1 cup of the reduced juices; scrape drippings free and stir meat, breaking into smaller pieces. Bake until juices have evaporated and drippings are browned, about 15 minutes, stirring occasionally. Repeat step, using remaining juices, and cook until meat edges are crisp and browned, 15 to 20 minutes longer. Season to taste with salt.
In a blender or food processor, whirl tomatillos, chilies, garlic and cilantro until coarsely pureed. Pour into a bowl. Stir in olive oil, avocado, and onion. Add lime juice and salt to taste.
Mix all the ingredients together.
You can warm tortillas in the microwave, it is better to heat them one by one on both sides in a non-stick pan over the stove and keep warm in a napkin lined basket.