1 tbsp. finely chopped cilantro
1/2 tsp. finely chopped fresh Mexican oregano (optional)
2 ripe tomatoes, cored and chopped
1 or 2 red and/or green jalapeños, stemmed and finely chopped while wearing gloves
1 clove garlic, minced
1 tablespoon fresh lime juice
1 tbsp. unsalted butter
1 lb. russet (best) or yukon gold potatoes, peeled
2 tsp. kosher salt
1 tsp. freshly ground black pepper, plus more to taste
1 tsp. ground cumin
1/2 cup canola oil or avocado oil
18 corn tortillas
You can top with any or all of the following: Thinly sliced green cabbage or lettuce, chopped tomatoes, pickled jalapeños, avocados and crumbled cotija or feta cheese or even cheddar in a pinch.
Mix cilantro, oregano, tomatoes, jalapeños, and garlic in a small bowl; set salsa aside.
Bring a medium saucepan of salted water to a boil, add potatoes, and cook until tender, about 25 minutes. Drain potatoes and transfer to a large bowl. Add minced garlic, butter, salt, pepper, and cumin, and mash until smooth. Set potato mixture aside.
Heat oil in a cast iron skillet over medium-high heat. Spread 3 or four heaping spoonfulls potato mixture over half of each tortilla, and fold over to form a taco. Working in batches, add tacos to oil and fry, turning once, until golden brown and crisp, about 3 minutes.
Stuff the cabbage, tomatoes, and cotija or others into tacos or spread on top; drizzle with salsa and sour cream (optional) before serving.