Parboil the potatoes first. This helps to soften their insides before the roasting begins, so you won’t be tempted to burn the outsides in exchange for less undercooked insides. About eight to ten minutes should work. The best way to check if they’re done is by poking a knife into a spud—if it meets little resistance (but doesn’t melt right in), you’re done.
Drain well. Make sure you let your potatoes sit for a bit to steam dry before putting them in the oven.
Don't overcrowd the pan. The potatoes should be in a single layer with sufficient space for the oven's heat to get distributed evenly. If you're in search of a great sheet pan, Nordic Ware's heat super evenly ($20 for 2, amazon.com).
Preheat your pan. This helps the outsides of your potato chunks get nice and crispy right away, so you’ll be less likely to overcook them.
Roast them hot. 425°F to 450°F is ideal. If your oven has a convection setting, use it (this will help them get crisper and brown more evenly). Just keep in mind that the convection fan circulating hot air inside will amp up the temperature, so set it closer to 400°F if you’re using convection heat.
Give them a few tosses. Wait about 20 minutes so your spuds will be less fragile, then flip or shake them around (this encourages even roasting) every 25 minutes or so. If they stick, use a thin metal spatula to gently dislodge pieces from the pan.
Pre-cook your garlic and herbs. This is a little bonus for those who like to add aromatics (we love rosemary and garlic) to your roasted potatoes. To avoid ending up with burnt-on garlic flavor, you can sauté minced garlic with herbs just until the starts to take on a golden color. Strain the oil from the solids—this way, you can toss the flavored oil with your potatoes and add those aromatics to your perfectly crispy potatoes at the end.
Now that you're inspired to perfect, Real Simple's got endless easy recipes for roasted spuds, like Garlic Roasted Potatoes, Paprika Pork Tenderloin With Roasted Potatoes and Dill Cream, Parmesan Roasted Potatoes, Sheet Tray Shrimp and Potatoes With Lemon, and of course, Melting Potatoes.