
Ingredients:
For the Potatoes:
- 6 large russet potatoes
- Olive oil (for rubbing)
- Salt
For the French Onion Filling:
- 4 tablespoons unsalted butter
- 2 tablespoons olive oil
- 4 large yellow onions, thinly sliced
- 1 teaspoon salt
- 1 teaspoon sugar (optional, helps caramelize)
- ½ teaspoon black pepper
- 2 cloves garlic, minced
- ½ cup dry white wine (or beef broth)
- ½ cup beef broth (low sodium)
- 1 teaspoon fresh thyme leaves (or ½ tsp dried)
- 1 teaspoon Worcestershire sauce
- ¾ cup sour cream or crème fraîche
- 1 ½ cups shredded Gruyère cheese (or Swiss, Comté)
- 1 cup shredded mozzarella (for melt/stretch)
- ½ cup grated Parmesan (optional, for topping)
Instructions:
1. Bake the Potatoes:
- Preheat oven to 400°F (200°C).
- Scrub potatoes clean. Prick each a few times with a fork.
- Rub with olive oil and sprinkle with salt.
- Bake directly on oven rack or a baking sheet for 1 hour, until fork tender.
- Cool slightly, then cut each potato in half lengthwise. Scoop out the insides into a large bowl, leaving a thin wall of potato inside each skin. Set skins aside on a baking sheet.
2. Caramelize the Onions:
- In a large skillet over medium-low heat, melt butter with olive oil.
- Add sliced onions and salt. Cook slowly for 30–40 minutes, stirring occasionally, until deep golden brown.
- Add sugar halfway through, if needed.
- Stir in garlic and cook 1–2 minutes.
- Deglaze with wine and cook until mostly evaporated.
- Add beef broth, Worcestershire sauce, pepper, and thyme. Simmer until thick and jammy. Set aside.
3. Make the Filling:
- Mash the scooped-out potato flesh with sour cream (or crème fraîche).
- Fold in the caramelized onions and 1 cup each of the shredded Gruyère and mozzarella.
- Taste and adjust seasoning with salt and pepper.
4. Assemble & Bake:
- Preheat oven to 375°F (190°C).
- Stuff the potato skins generously with the filling.
- Top with remaining cheese (Gruyère, mozzarella, Parmesan).
- Bake for 20–25 minutes, until hot and bubbling.
- Broil for 2–3 minutes at the end for a golden top, if desired.
Optional Add-ins:
- Bacon bits or pancetta in the filling.
- Chives or parsley for garnish.
- A dollop of French onion dip on top.
- Use mini potatoes for party-style bites!
Leftovers:
- Keep in fridge 3–4 days.
- Reheat in oven or air fryer for best texture.