Cut your potatoes in quarters or halves (depending on the size), or if using Yukon Golds cut into sixths.
Place the potatoes in a medium to large pot and cover with water, salt with a generous palm full of kosher salt. Set timer right now for 15 minutes. Place pot on stove and bring to a boil, then down to a simmer. Continue cooking at a simmer until your 15 minute timer goes off. Check at 13 minutes if you are nervous.
Drain water, then transfer potatoes to a sheet pan. Toss well with olive oil, salt, pepper, and rosemary. Place in oven and cook 15 minutes. Toss and return to oven for 15-20 more minutes, until the potatoes look crispy and browned, and creamy on the inside.
*The use of rosemary is optional. We love it when cooking the potatoes for brunch or as a side for steak. The flavors work great with those options. If you don't like rosemary, or it wouldn't compliment the flavors of your entrée, leave it out. We use rosemary about ½ the time we make these potatoes. See below for examples. If you do not have a convection oven, that is fine. Roast at the same temperature and stir the potatoes every 10 minutes to expose them to the heat. It may take 50 minutes total.