Best Potato & Red Onion Roast

This is the kind of side dish that disappears off the platter before the main course gets carved. Halved red-skinned potatoes and chunks of red onion get tossed with olive oil, dried rosemary, and parsley flakes, then go into a hot 400°F (200°C) oven for 40 minutes.

The key technique is the multiple turns during roasting. The recipe specifically calls for flipping the potatoes and onions several times during the 40-minute roast, which is what gets every cut surface caramelized rather than just the side that started face-down. Skipping this step leaves you with one crispy side and three pale ones.

Leaving the red potato skin on is non-optional. The skin crisps up during roasting and gives every bite a textural contrast that peeled potatoes can’t match. It also keeps the flesh from drying out.

Dried rosemary blooms in the oil as the potatoes roast, perfuming everything in the pan.

Kitchen Tips

• Use a deep-sided roasting pan, not a sheet pan. Steam needs room to escape, but you also want some height to keep the potatoes from rolling out as you flip them.
• Cut the onions into chunks the same size as the potato halves so they finish cooking at the same time.
• Don’t crowd the pan. Potatoes packed too tightly steam instead of brown.
• Hit them with flaky salt and a squeeze of lemon right after pulling from the oven for a brighter finish.

Variations

• Toss in whole garlic cloves still in their skins for a sweeter, jammy garlic note.
• Swap rosemary for fresh thyme or oregano for a different herbal profile.
• Add a tablespoon of grainy mustard or balsamic vinegar to the oil before tossing for tangier potatoes.