Hachis Parmentier with Pulled Beef and Gruyère

Why You’ll Love This Recipe

• Comfort classic with French flair: silky potatoes, savory beef, and a Gruyère crown.
• Perfect for leftovers—pulled beef or pot roast becomes company-worthy.
• Crowd-friendly bake that’s easy to prep ahead and reheat.
• Golden, crisp-cheesy top with rich, saucy onion-beef underneath.

Grocery List

• Produce: Yukon Gold potatoes, yellow onions, garlic, fresh thyme (or dried), flat-leaf parsley
• Dairy: Unsalted butter, whole milk, heavy cream, Gruyère cheese, 1 egg (optional)
• Pantry: Olive oil, tomato paste, dry red wine (optional), low-sodium beef stock, bay leaf, kosher salt, black and white pepper, ground nutmeg

Full Ingredients

Potato Topping

• 3 lb Yukon Gold potatoes, peeled and cut into 1 1/2-inch chunks
• 2 Tbsp kosher salt (for the boiling water)
• 6 Tbsp unsalted butter
• 1/2 cup whole milk, warmed
• 1/4 cup heavy cream, warmed
• 1 egg yolk (optional, for extra richness and browning)
• 1/2 to 3/4 tsp fine sea salt (to taste)
• 1/2 tsp white pepper (or black pepper)
• 1/8 tsp freshly grated nutmeg
• 6 oz Gruyère, coarsely grated (about 2 cups), divided: 1/2 cup for the mash, 1 1/2 cups for topping

Beef & Onion Filling

• 2 Tbsp olive oil
• 1 Tbsp unsalted butter
• 2 medium yellow onions, thinly sliced (about 3 cups)
• 2 garlic cloves, minced
• 1 Tbsp tomato paste
• 1 tsp fresh thyme leaves (or 1/2 tsp dried thyme)
• 1 bay leaf
• 1/2 cup dry red wine (or replace with 1/2 cup more stock)
• 1 cup low-sodium beef stock
• 1.75 lb cooked shredded beef or leftover pot roast, pulled into bite-size pieces
• 3/4 tsp kosher salt, plus more to taste
• 1/2 tsp freshly ground black pepper
• 1 tsp Worcestershire sauce (optional)
• 2 Tbsp chopped flat-leaf parsley

To Finish

• 1 Tbsp unsalted butter, for dotting the top
• Extra chopped parsley, for garnish

Step-by-Step Instructions

Step 1: Preheat and prepare your baking dish

Preheat the oven to 400°F (200°C) with a rack in the center. Lightly butter a 2-quart baking dish (about a 9-inch square or similar gratin). Set a large pot of water over high heat to boil for the potatoes.

Step 2: Cook and mash the potatoes

When the water boils, add 2 Tbsp kosher salt and the potato chunks. Simmer until very tender when pierced with a knife, 15–18 minutes. Drain well, then return potatoes to the hot pot and let steam-dry for 1–2 minutes (this keeps them fluffy). Mash with 6 Tbsp butter, warmed milk and cream, and the egg yolk (if using) until smooth. Season with 1/2 to 3/4 tsp fine salt, 1/2 tsp white pepper, and nutmeg. Fold in 1/2 cup grated Gruyère. Keep warm.

Step 3: Sauté the onions

While the potatoes cook, heat olive oil and 1 Tbsp butter in a large skillet over medium heat. Add onions and a pinch of salt. Cook, stirring occasionally, until soft and golden at the edges, 8–10 minutes. Stir in garlic, thyme, and tomato paste; cook 1 minute until fragrant.

Step 4: Build the saucy beef

Deglaze the pan with the red wine, scraping up any browned bits. Simmer 1–2 minutes to reduce slightly, then add beef stock and the bay leaf. Simmer 5–7 minutes until the liquid is glossy and syrupy. Fold in the shredded beef and Worcestershire (if using). Season with 3/4 tsp kosher salt and 1/2 tsp pepper (adjust to taste). Cook 2–3 minutes so the beef absorbs the sauce, then remove the bay leaf and stir in parsley.

Step 5: Assemble

Spread the beef-onion mixture in an even layer in the prepared dish. Spoon the mashed potatoes on top and smooth into a thick blanket, about 1 inch deep. Use a fork to make shallow ridges—these help the top crisp beautifully.

Step 6: Cheese and bake

Scatter the remaining 1 1/2 cups Gruyère over the potatoes and dot with 1 Tbsp butter. Bake at 400°F (200°C) for 25–30 minutes until the edges are bubbling and the top is golden in spots. For deeper color, broil 1–3 minutes, watching closely.

Step 7: Rest and serve

Let the Hachis Parmentier rest for 10 minutes to set. Garnish with extra parsley, scoop generous portions, and serve hot.

Pro Tips

• Use a potato ricer or food mill for the fluffiest, lump-free mash.
• Steam-drying the potatoes after draining prevents watery mash and helps a crisp top.
• Reduce the filling until it’s thick and glossy; too much liquid can make the casserole soupy.
• Rough up the potato surface with a fork—more peaks mean more golden, crispy bits under the Gruyère.
• Leftover pot roast works brilliantly: shred it and use some of its jus in place of part of the stock.

Variations

• Mushroom Boost: Add 8 oz sliced cremini mushrooms with the onions for extra savoriness.
• Lamb Parmentier: Substitute cooked shredded lamb for a French bistro twist; finish with rosemary instead of thyme.
• Root-Veg Mash: Swap 1 lb of the potatoes for celery root or parsnips; keep ratios of butter and dairy the same.

Storage & Make-Ahead

Assemble up to 24 hours ahead, cover, and refrigerate. Bake straight from the fridge at 375°F (190°C) for 35–45 minutes, then broil to brown. Leftovers keep 4 days refrigerated; reheat at 350°F (175°C) until hot, 20–25 minutes. To freeze, assemble but do not bake; wrap well and freeze up to 2 months. Thaw overnight in the refrigerator and bake as directed.

Nutrition (per serving)

Approximate: 820 calories; 42 g protein; 49 g carbohydrates; 43 g fat; 21 g saturated fat; 4 g fiber; 820 mg sodium. Values will vary with specific ingredients.