Thoroughly wash the potatoes. Halve the smaller ones, and quarter the larger potatoes so that they are all similar in size or about 1/2 inch.
On a parchment paper lined baking sheet, toss the potatoes in olive oil until evenly coated.
Sprinkle the rosemary on top and toss a few more times. Evenly spread out the potatoes on baking sheet.
Roast in oven for 20 minutes, remove, use a spatula to flip potatoes to opposite sides so that another side has contact with the pan and the chance to crisp and brown. Roast for another 15 to 20 minutes, until the desired crisp is achieved.
Season with salt to taste, approximately ½ tsp to start.
Prevent your screen from going dark
Notes
If you want to add a little extra depth to these potatoes, add 2 tsp minced garlic when you toss the potatoes with the rosemary.