For the sauce:
9 gaujillo chiles, seeds removed but keep the veins (you could use New Mexico as well, or ancho or mix if you needed)
1.5 cups of water
2 cloves of garlic roughly chopped
2 whole cloves crushed
a couple good grinds of black pepper
1/4 tsp or so of dried Mexican oregano (not Greek --- I'd just skip if I only had Greek)
salt to taste (it will be more than you think)
Toast the chiles on a griddle (medium heat) --- keeping them flat as possible with a spatula. You only need a few seconds for each one. You don't want them to burn or else you'll get a pretty bitter sauce.
After they've been toasted put them in a small pan can cover them with water. Bring to a simmer and then let cook for about five minutes. Remove from heat and let them sit for ten minutes or so --- they should be pretty plump and squishy. Strain the water and then tear into smaller pieces.
In a blender, put 1/2 cup of water, the garlic and the cloves. Blend really well. Slowly add the chiles (adding the additional cup of water a you go along). You really want this blended well. Pour the sauce through a fine sieve mesh into a bowl, pressing if needed. If you have a good blender you shouldn't have to press that hard to strain it, just some good stirring will do. The strained sauce now needs the oregano (I chowder it in the palm of my hand) and salt. It's really important you taste the sauce for enough salt. The salt will cut the bitterness.
The filling:
Really whatever you want. I use the following most of the time:
~ 1.25 lbs potatoes, diced
~ 1 onion finely chopped and salted (I prefer white --- avoid sweet onions)
~ 8 oz cheese cut into little cubes or shredded I guess (I like a sharp cheese here like cotija, but I've been happy with a sharp cheddar too)
~ some protein or whatever (tonight I used 1/2 cup quinoa you could also use cup of cooked ground beef or whatever)
Put the potatoes in salted water and boil them until tender (if you use quinoa you can add them during the last five-ten minutes or so of cooking). Drain and the mix with onions and cheese (mix in meat if using). Add about 1/8 cup of the sauce and mix. Taste for salt.
Assembly:
Make or heat your tortillas (how many depends on how big they are -- normal size corn tortillas you can get about 10-12).
Over lowish heat, heat about 1 tbs of corn oil in a pan large enough to fit whatever tortillas you are using (I like corn, but flour is fine too just don't get those huge burrito size ones). Add the sauce and stir in the oil until its cooked and the oil is incorporated (about ten minutes or so). With a spatula underneath it, dip a tortilla in the cooked sauce. Let it get covered in sauce (about 5 seconds at most) and pull out onto a flat work surface (I use a cutting board). Fill with some of the filling, roll up and put on a big plate you keep warm in the oven. Work fast and repeat with the other tortillas.