Pre-heat the oven to 400 degrees F. Grease a large baking tray or pan.
In a large bowl or large freezer bag, combine the potatoes, olive oil, rosemary, and sea salt. Toss to coat thoroughly.
Pour potatoes onto the baking tray and spread them out so that they are evenly spaced on the baking tray. It's okay if they're touching a bit but it's best if the potatoes are not stacked on top of each other at all.
Ground fresh black pepper evenly over top of the potatoes.
Bake for 25 minutes until golden brown. The potatoes should be tender and a bit soft when a fork is pierced into them. Baking for additional time if they're not quite done yet. Mine typically take about 33 minutes.