Make the Potato Filling
Peel and cut the potatoes into evenly sized chunks.
Place them in a large pot and cover with cold salted water.
Bring to a boil and cook for 15–20 minutes, or until fork tender.
Drain well and allow excess moisture to evaporate for 1–2 minutes.
Meanwhile, melt the butter in a skillet over medium heat.
Cook the onion until softened, about 5 minutes.
Add the garlic and cook another 30 seconds.
Mash the potatoes until smooth.
Stir in the onion mixture, milk, cumin, salt, and pepper.
Taste and adjust seasoning if needed.
Assemble the Tacos
Warm the tortillas briefly on a comal or dry skillet until flexible.
Place about 2–3 tablespoons of potato filling on one half of each tortilla.
Fold gently into a half moon.
Fry
Heat about ½ inch of vegetable oil in a skillet over medium heat.
Carefully fry the tacos 3–4 minutes per side until golden brown and crispy.
Transfer to paper towels to drain.
Serve
Top with:
shredded lettuce
queso fresco
Mexican crema
salsa verde or salsa roja
Serve immediately.