Bring a large pot of water to a boil over high heat. Add the potatoes and boil for 20 to 25 minutes, or until they're fork tender. Drain well.

Melt the butter in the same pot over medium heat. Add the garlic and cook for 30 seconds, until fragrant.

Add the potatoes back to the pot with the cumin, chili powder, and salt. Mash until smooth and creamy, then taste and add more salt if needed.

Warm the tortillas in a skillet or on a comal for a few seconds per side, until they're soft and pliable.

Spread about ¼ cup of the potato filling over half of each tortilla. Fold it over and press down gently so it sticks closed.

Heat the oil in a large skillet over medium-high heat. It's ready when the edge of a tortilla sizzles right away. Fry the tacos in batches for about 2 minutes per side, until golden and crispy, flipping them carefully with a spatula.

Transfer to a paper towel-lined plate to drain. Keep the finished tacos warm on a baking sheet in a 200°F oven while you fry the rest.

Stuff with shredded cabbage, cotija or queso fresco, crema, and your favorite salsa or hot sauce.