Make the flavored oil. Pour the oil or lard into a small saucepan and set over medium heat. When hot, add the chiles and garlic. Cook, stirring regularly until the garlic begins to brown, about 3 minutes. Pour into a blender and add 1 teaspoon salt. Secure the lid, remove the center, cover with a towel and blend as smooth as possible. Pour through a medium-mesh strainer into a small bowl.

Set up the 'basket.' Line a 6-quart slow cooker with napkins to cover the bottom, sides and enough overhang to fold in to cover the whole top. (You’ll need 2 heavy 18x18-inch napkins.) Then line the napkin-clad interior with a plastic bag. Turn the slow cooker on low and set the timer for 2 hours. Scatter ⅕ of the onion slices into the bottom of the lined slow cooker.

Heat the filling(s). Whichever filling(s) you’ve chosen, scoop it/them into something that’s microwave safe, cover and microwave until steaming. Cover to keep warm.

Heat the tortillas. Brush the tortillas on both sides thoroughly with the flavored oil or lard, then stack in 3 piles of 12. Slide each stack into a plastic bag and microwave 1 of the bags at 100% for 2 minutes. Let stand in the microwave for 2 minutes or so. Remove the first bag of tortillas from the microwave and begin heating the next bag.

Make the tacos and 'steam' them. Working quickly so that the tacos go into the slow cooker warm, scoop 2 rounded tablespoons of filling into a tortilla, fold it over and press flat. Lay into slow cooker over the onion. Continue with 7 more tortillas, shingling them in 2 rows over the bottom of the slow cooker. Scatter on another ⅕ of the onion, then make another layer of 8 tacos. Then onions, then tacos, then onions, then tacos. And finally, finish with onions. Fold the plastic and napkins up over the tacos. Set the lid in place and 'steam' for at least 30 minutes (They can hold up to 1 hour.)

Serve the tacos. Open up the slow cooker and start serving your tacos de canasta on plates, encouraging everyone to top them with salsa and pickled chiles.