Save this recipe for your next trip.
Last updated: July 2026 | 11 min read
Written by Alex Schult
Editor in Chief of 4wdTalk.com. 15+ years of off-road and overlanding experience with 1,000+ hours on the trail.
This recipe was tested on an actual overland trip. Amazon affiliate links support 4wdTalk.com at no extra cost to you.
In This Recipe
Why This Recipe Works for Overlanders
Foil packet potatoes and onions solves a problem every camp cook runs into. Most protein packets in this series cook fast, in 18 to 25 minutes. A side that needs a separate pan and a separate burner slows the whole dinner down. This packet drops onto the same bed of coals as the main course and finishes on the same clock.
I run this packet next to whatever protein is already cooking that night, whether it is chicken fajitas or BBQ pork chops. Baby red potatoes hold their shape better than russets over coals, and they do not need peeling. Sliced onion sweetens as it cooks and the garlic and rosemary carry through the whole packet.
This is the side dish that never gets old on a multi-day trip. Potatoes and onions both keep for a week or more in a cooler without special handling, so this recipe works on night one just as well as night five. Butter is the only ingredient that needs refrigeration, and even that holds fine in a cooler for the length of most trips.
Baby red potatoes are the reason this recipe hits 22 to 25 minutes instead of the 45 minutes a whole baking potato needs. Quartering them shortens the cook further by exposing more surface area to the coal heat. A packet built with smaller, evenly cut pieces cooks at a predictable pace every time.
Equipment You Need
This recipe uses the same core kit as every foil packet camping recipe. Heavy-duty aluminum foil at 0.94 mil (Reynolds Wrap Heavy Duty) handles the coal contact without tearing. Long-handled tongs pull the packet off coals without burned knuckles. Heat-resistant gloves rated to at least 500F handle the flip. A pairing knife checks the potatoes for doneness, since this recipe is judged by texture, not by temperature.
Gear for This Recipe
TempPro TempSwift 1 Sec Meat Thermometer Digital for Kitchen Cookin…
Ingredients
Serves 4 | Prep 10 min | Cook 25 min | Medium-hot coals
- 2 pounds baby red potatoes, quartered
- 1 large onion, sliced into half-moons
- 3 cloves garlic, minced
- 2 sprigs fresh rosemary, chopped
- 3 tablespoons butter, cut into pats
- Salt and black pepper, to taste
Step-by-Step Instructions
Home Prep
Quarter the baby red potatoes and slice the onion into half-moons at home, then store both in a sealed bag together. Mince the garlic and chop the rosemary into a separate small container. All three hold well in the cooler for several days before the packet gets assembled.
At camp, lay out a 16-inch square of heavy-duty foil per serving. Layer a quarter of the potatoes and onion in the center, sprinkle with garlic, rosemary, salt, and pepper, and top with a pat of butter. Flat-pack fold the packet, sealing every edge so steam builds inside and softens the potatoes.
At Camp
Build a bed of medium-hot coals, glowing orange with a layer of gray ash on top. Place the packets directly on the coals or on a grill grate set 2 to 3 inches above. Flip once at the midpoint of the cook.
Cook 22 to 25 minutes total, until a paring knife slides through a potato piece with no resistance. Open carefully, since trapped steam releases fast. Potatoes that still resist the knife need another 5 minutes back on the coals, sealed and flipped again.
Coal Bed Math
Coal temperature determines whether the potatoes turn fully tender in this recipe’s 22 to 25 minute window. Use this table to read your coal bed before placing packets.
| Coal Stage | Temperature | Best For |
|---|---|---|
| Hot | 500F+ | Searing, quick shrimp packets |
| Medium-Hot | 400-500F | Potatoes and onions, taco meat |
| Medium | 350-400F | Breakfast packets, vegetables |
| Medium-Low | 250-350F | Chocolate fondue, delicate desserts |
Field Tips
Cut the potatoes into even quarters, roughly the same size as each other. Uneven pieces cook at different rates, and you end up with some pieces mushy while others stay firm.
Do not skip the butter. Potatoes have almost no fat of their own, and without it, the pieces turn dry instead of rich.
If you are cooking above 7,000 feet, in the Sierras or up around Mammoth, build in extra time. Water boils at a lower temperature at altitude, so vegetables inside a sealed packet take longer to soften than they would at sea level. The USDA covers the science behind this on its high altitude cooking page. It is worth a read before any trip above the tree line.
Slice the onion into half-moons rather than dicing it small. Thin dice can burn against the hot foil before the potatoes finish softening, while half-moons hold their shape and sweeten slowly through the whole cook.
Coal and Cleanup Gear
Variations and Substitutions
The base foil packet potatoes and onions build takes well to swaps once the flat-pack fold feels natural. Try one change at a time so the cook time stays predictable.
- Bacon addition: Add a few pieces of pre-cooked bacon, crumbled into the packet before sealing, for a smokier, richer side.
- Parmesan finish: Toss the potatoes with grated parmesan right after opening the packet for a salty, savory crust.
- Sweet potato swap: Sweet potatoes work the same way as red potatoes, though they run slightly softer and sweeter once done.
- Bell pepper addition: Add a sliced bell pepper for color and a little crunch that holds up through the full cook time.
- Ranch seasoning: Swap the rosemary for a packet of dry ranch seasoning for a tangier, more familiar flavor.
- Low-sodium build: Skip the added salt and season with fresh cracked pepper and extra rosemary instead, to control sodium on a multi-day trip.
- Smashed potato style: Once the packet is open, smash each potato piece lightly with a fork so more surface area crisps against the hot foil.
- Herb swap: Fresh thyme works in place of rosemary for a milder, more versatile herb note.
Storage and Leftovers
Leftover foil packet potatoes and onions keep in a cooler at sub-40F for up to 3 days. Store the unopened packet directly in the cooler, since the foil already seals in the moisture. Reheat on medium coals or a camp stove burner for 8 to 10 minutes, turning once at the midpoint, until warmed through.
For longer trips, portion leftovers into a separate container rather than reheating the same packet twice. Potatoes dry out faster the second time they are reheated in an already-opened packet. A dedicated trash bag for used foil keeps the drawer system clean and supports a Leave No Trace pack-out.
Frequently Asked Questions
How do you know when foil packet potatoes and onions are done?
Slide a paring knife into a potato piece through the foil. It should meet no resistance. If the knife catches, reseal the packet and cook another 5 minutes on the coals.
Why are some potato pieces still firm while others are soft?
Uneven cutting is the usual cause. Cut every potato piece to roughly the same size so the whole packet finishes cooking at the same rate.
Can you use a different potato instead of baby red potatoes?
Yes. Sweet potatoes work the same way, though they run softer and sweeter once done. Russet potatoes work too, but cut them smaller since they need more time to soften than red potatoes.
Do you need to peel the potatoes first?
No. Baby red potatoes have thin skin that softens fully during the cook. Peeling is optional and mostly a texture preference.
Why does this recipe take longer at higher elevation?
Water boils at a lower temperature at altitude, so the steam trapped inside the packet is cooler. Vegetables need more time to soften above 7,000 feet than they do at sea level.
Can you make foil packet potatoes and onions ahead of time?
Yes. Quarter the potatoes and slice the onion up to 2 days ahead and store them together in the cooler. Assemble the full packet at camp right before cooking.
What other foil packet recipes pair well with this side?
This packet cooks on the same medium-hot coal bed as most protein packets in this series, including taco meat and lemon herb chicken, so it can go on at the same time.
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