Cut the potatoes into 2” chunks and place them on a large rimmed baking sheet.
Drizzle with olive oil and sprinkle with salt, pepper, garlic, and rosemary. Toss to coat well. Spread out into an even layer on the pan.
Roast for 35 to 45 minutes, stirring them every 15 minutes during cooking, until fork tender and golden brown and crispy on the outside. Toss with parsley and season to taste, if needed. Serve immediately.
Notes
Make sure you do not overcrowd the pan. Use a large enough sheet pan to spread the cut potatoes into a single layer with space between each piece. If the potatoes are too close, it’ll lead them to steam instead of roast.
Try to cut the potatoes as uniformly as possible so that the potatoes will bake evenly. If you have a few smaller pieces, keep a close eye on them and pull them off the sheet pan early if needed.
Avoid cutting the potatoes smaller than 2 inches. The size allows the inside to stay soft and fluffy while the exterior gets crispy and golden.
Make sure the oven is fully heated before putting the potatoes in the oven. If the oven is not hot enough, it will take too long for the outside to brown, and the inside will get mushy.
A large spatula is an excellent tool in the kitchen as it helps you quickly flip the potatoes.
If you’re unsure you’ve cooked through the potatoes, check that they can be easily pierced with a fork.