. In her version diced onions, egg and dried Italian (I know - Italian!) herbs were mixed into the ground beef and the patties were lightly floured and pan-seared. In my version, there’s slow-cooked caramelized onions, classic mushroom duxelles (‘mushroom
hash’), Dijon mustard and Brie cheese; classic French flavors that are very reminiscent of French Onion Soup.
Note: In the picture, I stacked two finished burgers on top of each other…just for effect!! data-pin-do=)
A French Hamburger: with Caramelized Onions & Brie on Brioche by Foodie’s Chef Laura Brennan.
February 23, 2023
I recently watched a very old episode of Julia Child on WGBH in which she made French hamburgers and proclaimed that the French were equally fond of hamburgers (‘bifteck hache’). In her version diced onions, egg and dried Italian (I know - Italian!) herbs were mixed into the ground beef and the patties were lightly floured and pan-seared. In my version, there’s slow-cooked caramelized onions, classic mushroom duxelles (‘mushroom
hash’), Dijon mustard and Brie cheese; classic French flavors that are very reminiscent of French Onion Soup.
Note: In the picture, I stacked two finished burgers on top of each other…just for effect!!
- Prep: 1 hrs
- Cook: 1 hrs
- Yields: I made three (3) 6-ounce burgers, but you could make four (4) smaller 4-ounce burgers.
Ingredients
for the caramelized onions:
2 pounds sweet or white onions
2 tablespoons olive oil
2 tablespoons unsalted butter
pinch dried thyme leaves
Kosher salt & fresh cracked black pepper
for the patties:
1-pound ground beef
1 recipe prepared mushroom duxelles, less 2 tablespoons set aside for the sauce (recipe below)
1 teaspoon kosher salt
A few twists of fresh ground black pepper (fresh twists from the peppermill!)
for the mushroom duxelles:
1-10/12-ounce package white button or baby portabella mushrooms
2 Tablespoons very finely minced shallots
1-2 Tablespoons olive oil
1-2 Tablespoons unsalted butter
Optional: 2 tablespoons light cream or half & half
Kosher salt and fresh ground black pepper to taste
Optional: 1 teaspoon fresh or freeze-dried chives
for the sauce:
½ cup prepared plain mayonnaise
1 teaspoon Dijon mustard
2 tablespoons prepared mushroom duxelles (set aside from above)
to finish:
3-4 brioche burger buns, split
2 tablespoons softened butter
3-4 ounces Brie cheese, sliced
Directions
Begin by preparing the caramelized onions: Peel the onions and slice them in half and then thinly slice them following the ‘rings’ of the onions. Heat the oil in a large sauté pan to medium hot. Add the butter and then the sliced onions. Season with salt and stir to combine the onions
with the cooking fat. Cook and stir over medium-low heat as the onions begin to wilt and turn brown (caramelize). This process may take 20-30 minutes. Be patient and watch them to prevent burning. When they have taken on a deep brown caramel color they are finished. Add a tiny pinch of dried (or
fresh thyme), and taste for seasoning. Add more kosher salt and fresh black pepper to taste. Remove the cooked onions from the pan and set aside at room temperature.
Make the mushroom duxelles: Rinse the mushrooms in a strainer/colander under cool running
water and shake off the excess water. (Alternately, with a damp towel, wipe each mushroom
clean.)
Pop out the stems and discard or save to flavor a future soup or stock. Slice and chop the mushrooms into a very small dice. Set aside in a bowl. Finely chop the shallots. Heat a small sauté pan on medium-low heat, add the oil and butter. Add the chopped shallots along with a pinch of kosher salt. Sauté the shallots over low heat until they are translucent. Watch them and stir often as shallots have a tendency to quickly burn. Add the chopped mushrooms along with another pinch of salt. Stir to combine. Cover the pan, turn heat down and cook until mushrooms begin to exude their juices. Remove lid and stir until the juices have evaporated. Add the light cream/half & half if using. Cook just until the cream has been absorbed. Taste and adjust seasoning. Remove to a plate or bowl to cool.
Make the sauce: In a small bowl combine ½ cup prepared plain mayonnaise with ½ teaspoon
of Dijon mustard. Stir to combine. Mix in 2 tablespoons of the finished, cooled mushroom
duxelles from above. Stir to combine. Taste and adjust seasoning. Optional: add 1 teaspoon
chives and or parsley if desired. Set aside.
Butter the buns and toast face down briefly in the oven on a sheet pan until golden brown, 3 to
4 minutes. Remove to a plate. Slice the Brie cheese into thin slices. Set aside.
Make and cook the patties: Add the ground beef to a large bowl and mix in the rest of the prepared mushroom duxelles. Add ½ teaspoon of kosher salt and a few twists of fresh-ground black pepper from the mill. Mix well. Form the meat into 3 or 4 patties. I cooked the burgers on a sheet pan in the oven but you could certainly sauté them. I cooked them for about 6-8 minutes and then added 2-3 small slices of brie cheese on top to melt VERY briefly---just a minute. You don’t want the cheese to completely melt away and the size of the burger will dictate how long they will take to cook.
Remove sheet pan from oven and let the burgers rest for a few minutes.
Build the burgers: Spread some mushroom duxelles sauce on the insides of the toasted buns.
Slide a cooked burger on the bottom of one bun and add a tablespoon or two or the
caramelized onions on top. Cover with the other half of the toasted bun. Repeat.
Serve immediately.
