Season the pork shoulder with salt and black pepper, rubbing in thoroughly on all sides. Be generous.
Place the pork in the slow cooker. Add picante sauce, Worcestershire sauce, bay leaf, rosemary and oregano. Cook for 8 hours on low or 4 hours on high. The pork should be so tender that meat falls apart easily. Remove pork from slow cooker and shred the meat using two forks, removing excess fat. Taste and adjust seasoning if needed.
Heat oven broil. Line one baking sheet with foil and spray with cooking oil.
Place carnitas onto a baking sheet, with HALF of the juices, and broil until most of the pork looks golden, crisp and crusted, about 4 minutes. Remove from oven.
To serve tostadas spread a large spoonful of mashed avocado, pork carnitas, top it with fennel and mango salsa, and sprinkle crumbled queso fresco. Enjoy
I added some brown sugar because we love the sweet and spicy combo but if you want the spiciness to be the hero flavor you can skip it. Looking for more Slow Cooker recipes?