Ingredients
Equipment
Method
Roast the potatoes
- Preheat oven to 425F, then toss baby potatoes with olive oil, salt, and black pepper in an oven-safe cast iron skillet until evenly coated. Make sure the potatoes are spread in a single layer for browning.
- Roast at 425F for 30-35 minutes, until golden and crispy. Look for browned edges and a dry, crisp surface.
Make the jammy onion topping
- Cook yellow onions in butter over medium-low heat for 25 minutes until deep golden and jammy. Stir occasionally so the onions soften and caramelize without burning.
- Stir in fresh thyme leaves, beef broth, and Worcestershire sauce, then simmer until the liquid is absorbed. Continue cooking until the mixture turns glossy and clings to the onions.
Assemble and finish
- Spoon the jammy onions over the roasted potatoes, spreading them evenly across the top. Use a spoon to press lightly so the onions sit on the crisp surface.
- Bake at 425F for 8-10 minutes, until the Gruyere is melted and bubbly. Watch for bubbling cheese and lightly browned spots.
Notes
For the crispiest potatoes, keep the skillet crowded no more than needed and roast until the edges are clearly browned before adding the onions and cheese. Refrigerate leftovers up to 3 days in an airtight container and reheat in a 400F oven until hot and re-crisped. Freezing is not recommended because the potatoes can soften after thawing. For a simple dietary swap, use a plant-based butter and a dairy-free cheese that melts well in the final bake.