Irish Nachos take the best parts of a loaded baked potato and serve them up hot and crispy on a platter. Fried potato slices are the perfect vehicle for cheese, bacon, sour cream, tomatoes, and anything else you're craving.
Using a mandoline or a sharp chef's knife, slice the potatoes into 1/4-inch thick pieces. Rinse the slices under cold water, then store in a large bowl of water while slicing the remaining potatoes.
Drain potatoes. In a large saucepan over high heat, combine vinegar and 2 quarts water. Bring to a boil.
Add potatoes and cook for 5 minutes. Drain well and spread in a single layer on rimmed baking sheets lined with paper towels. Dry five minutes.
In a Dutch oven, large pot, or deep fryer, heat oil to 400 degrees. Add 1/2 of potato slices and cook, stirring and flipping constantly with wire mesh spider or slotted spoon, until potatoes release no more bubbles, about 3 to 5 minutes (smaller chips may cook faster than large ones and should be removed from the oil as they finish).
Transfer potato slices to a rimmed baking sheet lined with paper towels, and sprinkle with salt. Repeat with remaining potato slices.
To make the nachos:
Preheat oven to 450 degrees. Transfer potato slices to a broiler-proof pie plate or serving platter.
Top with cheese and bacon. Bake until the cheese is hot and bubbly, about 3 minutes. Remove from oven and top with sour cream, tomato, scallions, and jalapeño slices, if using.
Potatoes: Opt for starchy potatoes like Russets so they're sturdy enough to slice, cook, and hold toppings. For even cooking, cut into slices of equal thickness (I suggest using a mandoline). Peeling the potatoes is optional.
White vinegar: Parboil the potato slices in water and 2 tablespoons of vinegar. The acid will help the potato slices hold their shape while cooking.
Oil for frying: Choose a neutral oil with a high smoke point such as avocado oil, canola oil, or peanut oil. Avoid your best olive oil here as it has a strong flavor and will probably set off your smoke detector in the process.
Bacon: Crisp it up in a skillet or on the stove; here's how to fry bacon perfectly.
Yield: This recipe makes about 4 cups of Irish Nachos, enough for 4 servings, 1 cup each (plus toppings).
Storage: Store leftovers in an airtight container in the refrigerator up to 4 days. Reheat in the oven at 450 degrees until the potatoes are warm and the cheese gets melty again, about 10 to 15 minutes.