Introduction

This oven-baked 5-ingredient beef and onion foil packet dinner is a simple, hearty meal perfect for busy nights. Combining tender beef, sweet onions, and tender baby potatoes, it cooks together in foil for easy cleanup and great flavor.

This dish shows a foil packet opened on a white marbled surface, filled with three main layers. The bottom layer is a shiny, oily mix of cooked, sliced onions in long, pale yellow strips with visible char marks. On top and around the onions are whole baby potatoes in two colors: golden yellow and deep red, each with a soft, cooked texture and a light sprinkling of green herbs. The top layer consists of four slices of grilled steak, dark brown with grill lines and also sprinkled with chopped green herbs, arranged neatly in a row on one side of the packet. photo taken with an iphone --ar 4:5 --v 7

Ingredients

1 1/2 pounds thinly sliced beef steak (such as sirloin or round)
2 large yellow onions, thinly sliced

1 1/2 pounds baby potatoes, halved (or small potatoes cut into 1-inch chunks)
3 tablespoons olive oil

2 teaspoons steak seasoning (or your favorite all-purpose seasoning blend)
Salt and black pepper, to taste (optional)

Nonstick cooking spray (for foil, optional)

Instructions

Step 1: Preheat your oven to 400°F (200°C). Line a large baking sheet with foil for easy cleanup. Tear off 4 large sheets of heavy-duty aluminum foil, about 12×18 inches each. Lightly spray the center of each with nonstick cooking spray if desired to prevent sticking.
Step 2: Prepare the vegetables by thinly slicing the onions and halving the baby potatoes (or cutting larger potatoes into 1-inch chunks). Pat the beef dry and slice into strips if not already thinly sliced.

Step 3: In a large bowl, toss the potatoes and onions with olive oil, steak seasoning, and a pinch of salt and black pepper if needed. This ensures even seasoning on all pieces.
Step 4: Divide the seasoned onion and potato mixture evenly among the four foil sheets, placing the mixture in the center of each. Top each with an equal portion of sliced beef, spreading the meat out slightly for even cooking.
Step 5: Seal the packets by bringing the long sides of the foil together over the filling and folding them down tightly. Then roll up the short ends to form a snug packet, leaving a little space inside for air circulation and steam.

Step 6: Place the foil packets on the prepared baking sheet and bake for 30–35 minutes, until potatoes are tender and beef is cooked through. For less cooked beef, open the packets during the last 5 minutes to release steam and reduce cooking time slightly.
Step 7: Carefully open one packet (watch for hot steam) and check a potato for doneness. If needed, reseal and bake another 5–10 minutes. When done, remove from the oven and let the packets rest for 3–5 minutes before serving.
Step 8: Serve the foil packets directly on plates or transfer contents to shallow bowls. Spoon any juices over the top to enjoy the full onion and beef flavor.

Tips & Variations

Use different seasonings like garlic powder, smoked paprika, or fresh herbs to customize the flavor.
Swap baby potatoes for sweet potatoes or add sliced bell peppers for more color and nutrition.
If you don’t have foil, you can cook this in a covered baking dish but expect a bit more cleanup.

For extra richness, add a pat of butter on top of each packet before sealing.

Storage

Store leftover foil packet contents in an airtight container in the refrigerator for up to 3 days. Reheat gently in the microwave or in a covered skillet over medium heat until warmed through to prevent dry meat and potatoes.

How to Serve

The image shows a foil packet opened to reveal the contents inside, placed on a white marbled surface. Inside the foil, there are four pieces of grilled steak, dark brown with visible grill marks and garnished with small green parsley flakes, positioned on the left side. Next to the steak, on the right side, are golden and red baby potatoes cut in halves, with a slight crispy texture and sprinkled with herbs and small black pepper bits. Mixed around the potatoes and steak are sautéed yellowish onion slices that are soft and lightly browned. The foil packet is crinkled and shiny, reflecting light as it holds the food neatly together. Photo taken with an iphone --ar 4:5 --v 7

Serve this delicious recipe with your favorite sides.

FAQs

Can I use frozen beef for this recipe?

It’s best to use fresh or fully thawed beef for even cooking and best texture. If using frozen, thaw completely before assembling the packets.

How can I tell if the potatoes are cooked through?

Carefully open one packet and pierce a potato with a fork or skewer. If it slides in easily without resistance, the potatoes are tender and ready.