Place oven rack on the bottom third of the oven and preheat to 450 degrees.
Cut potatoes into thick fry shapes equal thickness. They shrink during cooking so be sure to cut them 2x as big as you want the finished fries to be.
Bring a pot of water to boil over high heat. Add the potatoes and boil until they are soft and close to breaking but still holding shape, about 7-8 minutes. Strain them by covering the pot with a lid, slightly cracked. Do not tip them into a strainer as they will all break and fall apart. Drain them very gently.
In a large roasting pan, lay out the potato pieces in a single layer, being sure none of the potatoes are overlapping. Pour on enough oil to thoroughly coat all the pieces and enough for the oil to completely cover the bottom of the pan. Shake the pan to coat the pieces and get the fries evenly distributed. If you are cooking for a crowd you will need two roasting pans or baking sheets. Do not cook on a pan that's covered in foil or parchment paper, the potatoes must be in contact with the hot metal surface.
Roast the potatoes for about 30-35 minutes, flip a fry over to see if it's a nice light to medium brown on the bottom. Once nicely browned, flip each fry over so the opposite side can brown. Continue to roast them until they're brown and crispy, about another 30 minutes, but be sure to check on them every 15 minutes to avoid overcooking them — very brown will taste burned.
While the fries are finishing, place a few layers of paper towels in a large bowl. Lightly pat the fries to soak up the excess oil. Remove paper towels and season the fries in the bowl and then toss to coat. I use coarse salt, parsley, and parmesan cheese.Other seasoning options: seasoned salt, rosemary, black pepper, cayenne, paprika, etc.