Preheat the oven to 375 degrees F. Rinse the potatoes and peel them. Cut each in half, then cut each of those pieces in half. If some of the potatoes are large, you may need to cut those pieces in half again.
Spread the potatoes in a single layer in a 10x15 glass pan. If you don't have a pan that large, fit what you can in a 9x13 glass baking dish and put the extras in an 8x8 glass pan. (Glass works better in this recipe than a baking sheet.)
Sprinkle on the onion powder and Seasonello evenly. Slice the butter into squares ½-inch thick and scatter them on top of the potatoes.
Bake uncovered for 1 hour and 15 minutes, stirring once at the halfway point. The potatoes should be browned on some sides, but not all. For the best texture, let the potatoes rest for 10 minutes before serving them.
Store leftovers covered in the refrigerator for up to four days.
Notes
Seasonello is an Italian seasoning that consists of sea salt, rosemary, garlic, sage and pepper. It's excellent on vegetables, seafood, chicken and all kinds of meat. You can buy it online or at Italian import stores.
If you don't want to buy the seasoning, you can use your own combination.
Note, if you want to substitute table salt for the sea salt, use half a teaspoon of table salt in this recipe. Then, taste the potatoes after they're done to see if you need to add more.