Start by cooking a finely chopped onion in some oil over medium heat. Once softened, add 2 lbs. ground beef and cook until browned. Once browned you can drain off some fat if you want.
Add 4 minced garlic cloves to the beef mixture and give it a quick saute for 30 seconds or so. Then add the remaining ingredients: 3-6 minced chipotles in adobo, 1 tablespoon adobo sauce from the can, 2 teaspoons chile powder (optional), 1.5 teaspoons salt, 1/2 teaspoon cumin, 2 teaspoons Mexican oregano, freshly cracked black pepper, and a splash of water. Combine well and once heated through take a final taste for seasoning. I added another pinch of salt and Mexican oregano to this batch. Note: I used six chipotles for this batch and it had some real heat! Start with less chipotles for a milder batch.
To make the taquitos, start by warming up the corn tortillas. I covered them with damp paper towels and microwaved them for a minute or so. Other ways to warm up corn tortillas. Add 2-3 tablespoons of the Beef mixture to each tortilla along with strips of cheese (or shredded cheese). Roll tight and place them seam side down on a baking sheet. To cook them, simply add a thin layer of oil to the taquitos and bake them in a 400F oven for 15-20 minutes. I usually start taking peeks after 15 minutes and take them out when the edges are turning darker brown. Serve immediately. Note: you can use an olive oil sprayer or pastry brush to give them a thin layer of oil, but I've used oily fingers in the past and it works just as well :)
If you're making the Salsa de Aguacate, combine the following ingredients in a blender or food processor: the flesh of a ripe avocado, 1/4 cup water, juice of 1 lime, 4-5 sprigs of cilantro, 1/2 peeled garlic clove, and 1/4 teaspoon salt. Combine well and taste for seasoning. For a thinner consistency add additional splashes of water and re-blend.
Continue rolling taquitos until all of the ground beef mixture is used. Add leftover taquitos to freezer safe bags and store in the freezer. To reheat, simply add a thin layer of oil to the taquitos and bake in a 400F oven. They'll need a similar amount of time to bake when pulling them from the freezer, just a tad longer.