A skillet with mashed potatoes and roasted meat on a blue surface
Photography, Lauren Vandenbrook

Mary Berg’s French Onion Pot Roast

A comfort food staple that's perfect for making ahead.

The ultimate low and slow comfort staple with a little je ne sais quoi, this recipe is one of my favourite make-aheads that, even after a few days, I’d happily serve to company (yes, even the mashed potatoes!). The sweetness of caramelized onions paired with rich and hearty slow-cooked beef is made all the more indulgent when paired with ultra cheesy, very French-feeling mashed potatoes. –Mary Berg

A skillet with mashed potatoes and roasted meat on a blue surface

Mary Berg's French Onion Pot Roast

Mary Berg's recipe for cheesy French-inspired mashed potatoes with a classic pot roast and onion gravy.
Course Main Course
Cuisine Canadian, French
Servings 6



  • 3 lb chuck roast
  • kosher salt
  • freshly ground black pepper
  • 1 tbsp olive oil
  • 2 tbsp butter
  • 8 yellow onions thinly sliced
  • 3 garlic cloves chopped
  • tsp packed brown sugar
  • ¼ cup brandy
  • 1 tsp all-purpose flour
  • 2½-3 cups low-sodium beef broth
  • 4 sprigs thyme
  • 2 bay leaves


  • lb yellow potatoes peeled and quartered
  • 4 garlic cloves
  • 4 sprigs thyme
  • kosher salt
  • 6 tbsp butter
  • ½ cup heavy cream
  • ¼ cup buttermilk
  • 7 oz Gruyère cheese grated
  • oz mozzarella cheese grated


  • Preheat your oven to 300°F.
  • Place a Dutch oven over medium-high heat. Using paper towel, dry off the outside of the roast and season well with salt and pepper. Add the oil to the pan and sear the roast until golden brown all over, 3 to 5 minutes per side. Remove the roast to a baking sheet or large bowl to catch any juices and set aside.
  • Turn the heat down to low, add the butter and onions, and season with salt and pepper. Cook for 20 to 25 minutes or until the onions are cooked down and golden, stirring occasionally. Stir in the garlic and sugar and increase the heat to medium. Cook for 5 to 10 minutes, stirring frequently, until deeply golden brown and well caramelized.
  • Deglaze the pan with brandy and allow to cook away for 1 to 2 minutes. Sprinkle the flour over the onions and stir well to combine. While stirring, slowly pour in 2½ cups of beef broth. Add the roast back to the pan and, if needed, add more beef broth to come halfway up the roast. Stir in the thyme and bay leaves and turn the heat up to medium-high and bring to a simmer.
  • Place the lid on the pan and transfer the roast to the oven for 3 to 3½ hours or until the roast is fork tender. When tender, remove the roast from the oven, leave the lid on, and set aside to rest while you make the potatoes.
  • Place the potatoes in a pot and cover with cold water. Add the garlic and thyme, generously season with salt, and bring to a boil over medium-high heat. Cook the potatoes until fork tender, 15 to 20 minutes. Drain, discard the thyme and return the potatoes and garlic to the pot.
  • Roughly mash the potatoes and garlic with a masher and add the butter, cream and buttermilk. Using a hand mixer, beat the potatoes until smooth and creamy. Switch to a heatproof spatula or wooden spoon and gradually begin stirring in the grated Gruyère and mozzarella, adding about a handful at a time. Season the potatoes with salt to taste and, if needed, add a splash more cream or buttermilk until the potatoes reach your desired consistency.
  • Using tongs or two forks, pull the beef apart into large chunks and serve over the cheesy mashed potatoes with a few ladlefuls of the onion gravy.


If you’re looking to get ahead, you can store the beef, gravy and all, in the Dutch oven and transfer the potatoes to a greased baking dish. Cover and keep in the fridge for up to 3 days. To reheat, leave the beef covered and place over medium-low heat. Uncover the potatoes and transfer to a 375°F oven. Cook both for 35 to 45 minutes or until heated through and the potatoes are lightly golden brown and crisp around the edges.

A cookbook cover in a light frame

Excerpted from In Mary’s Kitchen by Mary Berg. Copyright © 2023 Mary Berg. Photographs by Lauren Vandenbrook. Published by Appetite by Random House®, a division of Penguin Random House Canada Limited. Reproduced by arrangement with the Publisher. All rights reserved.
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