Potato, Poblano, and Cotija Tacos

The contest over at food52 last week was for your best cheap feast, and I really wanted to enter it (I love kitchen thrifty-ness challenges!), but I couldn't think of anything that would be better than these fantastic potato tacos, which are sadly not my own invention. So I thought I'd share them here instead! They are dead simple: boiled potatoes cooked in fat with onions, roasted peppers, and cheese until golden and crispy. Piled into warm corn tortillas with guacamole and a side of beans, they make a mean, and cheap, meal.

For south Austinites, I have been buying my corn tortillas from Tortilleria Rio Grande #2, which is in the strip mall with the (terrible) HEB at the corner of S.1st and William Cannon. The tortillas are much better than anything you can buy at the grocery store and so cheap. And! And! This place sells our favorite tacos in the world.  The desebrada is particularly transcendent- juicy stewed beef with little else, but I've really loved everything I've tried there. To me, it is on par with the much-hyped (and deservedly so) Taco More, but so much closer to home.

Potato, Poblano, and Cotija Tacos
adapted from Rick Bayless's Papas con Rajas recipe in Authentic Mexican

• 1 lb yukon gold potatoes, peeled and cut into 1-inch chunks
• 3 medium poblano peppers (you can substitute any large green non-bell pepper)
• 1/4 cup lard or vegetable oil, plus extra as needed
• 1 small onion, peeled, halved, and thinly sliced
• 1 cup crumbled cotija cheese
• kosher salt
• corn tortillas, warmed
• guacamole and limes, for serving

1. Put the potatoes in a medium-sized pot of salted water, bring to a boil, and then lower the heat and simmer for 15-20 minutes, or until tender (a knife inserted into a potato should slip right out). 
2. While the potatoes are boiling, roast your peppers. Place an oven rack in the highest position, turn your broiler to high, and put the peppers directly on the rack under the broiler.  Broil, turning occasionally, until the outsides are charred and crackly, about 10 minutes total. Remove the peppers to a bowl and cover with a dish cloth so they can continue to cook in their own steam for 5 more minutes or so. Then peel the charred skin from the peppers, remove the stem and seeds, and chop the flesh into 1/8-inch strips.
3. While the peppers are in the bowl steaming, heat a cast iron skillet over medium heat and add the lard or oil. When hot, add the sliced onions and cook, stirring occasionally, but not letting them get too brown.
4. When the potatoes are tender, drain them and add them to the pot with the browning onions, using a thin metal spatula to scoop and flip the potatoes often, so that they and the onions get brown and crispy-edged.  I usually splash in some extra oil at this point too, because I like the potatoes to get really crispy, and I like fat, but it's not necessary. I keep half an eye on the potatoes while heating up the beans and tortillas and making guacamole, but I probably cook them for 10-15 more minutes in the pan. When they look done to your liking, mix in the poblano strips and the crumbled cheese and let them hang out in the pan a minute more, so the cheese gets melty and a little brown in places. Season with kosher salt to taste. 
5. Serve the potatoes in warmed corn tortillas with guacamole and limes and a side of beans.