Hasselback potatoes are a type of potato dish, not a variety of potato, as is sometimes mistakenly believed. The name is derived from the restaurant where they were first introduced in the 1940s, Hasselbacken in Stockholm, Sweden which opened in that city in 1748 and where they are called hasselbackspotatis. Hasselback potatoes are a simple dish, and in their simplest form, are nothing more than whole potatoes cut in such a way as to resemble a fan or accordion when roasted. The outside of the potato becomes crisp and brown while the inside is soft and creamy.
Certain varieties of potato are better suited to this type of dish than others. Medium sized potatoes work best. Very small potatoes such as fingerling or new potatoes are not good candidates. Very large potatoes are also not well suited to the dish as the portion size is not appropriate for single servings. Ideally, one or two whole potatoes per person are desired. Potatoes with an oblong or oval shape are most often used, and a typical baking potato is perfectly fine for this dish.
What distinguishes hasselback potatoes from other roasted potato dishes or even a basic baked potato is the way the potato is prepared for roasting. The potato, which may or may not be peeled is cut into very thin slices but without completing the cuts that would separate the potato into individual slices, leaving all the slices connected along the bottom of the potato. This requires careful knife work but is not too difficult.
In their original and simplest form, hasselback potatoes are usually drizzled with melted butter and seasoned lightly with salt and pepper and topped with bread crumbs. This is important as the butter is absorbed into the potato during roasting, resulting in a soft, creamy interior and a crispy outside. As the potato cooks, the individual slices separate slightly and give the finished dish its distinctive look.
Like many older dishes, hasselback potatoes have undergone a very wide range of variations, and many chefs and home cooks have their favorite version of the recipe. Almost any seasoning may be used, and some recipes call for things like lemon, fresh herbs, Parmesan cheese, or fresh garlic. All of these variations are simply products of the preferences of individuals and are still properly called hasselback potatoes. It is the slicing and roasting procedures that distinguish these dishes as hasselback potatoes rather than the variations on seasonings or toppings.