Preheat your oven to 360 or 400 Fahrenheit or somewhere around there. Put a generous amount of olive oil in the baking dish. You’re going to want the potatoes to brown nicely, so don’t skimp. Use normal olive oil if you have it. You can use extra virgin, but you’d be wasting money. Wash and cut your red potatoes into even, bite-sized pieces, leaving the red skin on. Put the potatoes in the baking dish with the oil, and sprinkle over the salt and rosemary, trying to spread it equally, and not to over-season. I personally like to use kosher salt, just because I think it’s tastier, but go ahead and use regular salt if you want. Fresh rosemary also helps, but once again, it doesn’t really matter that much. Mix the potatoes and seasoning with the oil in the pan, covering all of the potatoes in oil. Put the potatoes in the oven and keep an eye on them. It’s really impossible to give an exact time, but don’t worry, because it’s pretty hard to mess this up. Just keep an eye on them to make sure they don’t burn. When you think they’re done, turn the oven to broil and let them brown on top. This will happen quickly, so be careful. Once they’re done browning, scrape the potatoes from the pan (they may stick a little. Try to scrape them off so that the crust stays on the potato, not the dish), and serve! Works well as an accompaniment to any basic or Mediterranean food.