French Onion Burgers

🥘 Ingredients

• beef stock concentrate
  1 unit
• black pepper
  1 pinch
• brioche buns
  2 units
• butter
  1 tbsp
• flour
  1 tbsp
• ground beef
  10 oz
• gruyère cheese
  2 oz
• kale
  1 bunch
• milk
  ½ cup
• nutmeg
  1 pinch
• olive oil
  3 tbsp
• salt
  1 pinch
• sugar
  1 tsp
• thyme
  2 sprigs
• water
  ¼ cup
• yellow onion
  1 unit

🍳 Cookware

• baking sheet
• large pan
• grater
• small pot

1. 

   1

   yellow onion kale thyme beef stock concentrate gruyère cheese flour milk nutmeg ground beef brioche buns olive oil sugar butter salt black pepper water

   yellow onion: 1 unit, kale: 1 bunch, thyme: 2 sprigs, beef stock concentrate: 1 unit, gruyère cheese: 2 oz, flour: 1 tbsp, milk: ½ cup, nutmeg: 1 pinch, ground beef: 10 oz, brioche buns: 2 units, olive oil: 3 tbsp, sugar: 1 tsp, butter: 1 tbsp, salt: 1 pinch, black pepper: 1 pinch, water: ¼ cup
2. 

   2

   Wash and dry all produce. Preheat oven to 350 degrees. Halve, peel, and thinly slice yellow onion. Remove stems and large ribs from kale, then tear leaves into bite-sized pieces. Toss kale on a baking sheet with a drizzle of olive oil and a pinch of salt and black pepper. Bake in oven until crisp ⏱️ 10 minutes . Keep an eye on them as they can burn quickly.
3. 

   3

   Heat a drizzle of olive oil in a large pan over medium heat. Add yellow onion and thyme sprigs. Cook, tossing, until soft and browned ⏱️ 7 minutes . Stir in beef stock concentrate, sugar, and water. Simmer until onion is jammy ⏱️ 2 minutes . Remove and discard thyme sprigs. Remove onion from pan and set aside. Wipe out pan.
4. 

   4

   Meanwhile, grate gruyère cheese on large holes of a grater . Melt butter in a small pot over medium heat. Add flour and stir until lightly toasted ⏱️ 1 minute . Slowly whisk in milk, then simmer until thickened ⏱️ 1 minute . Season with nutmeg, salt, and black pepper. Set aside off heat.
5. 

   5

   Shape ground beef into two evenly sized patties (slightly larger than the buns). Season all over with salt and black pepper. Heat a drizzle of oil in the pan used for onion over medium-high heat. Add burgers and cook until just shy of desired doneness ⏱️ 3 minutes per side. Sprinkle cheese on top of each burger, cover pan, and cook until cheese melts ⏱️ 1 minute .
6. 

   6

   While burgers cook, split brioche buns in half and place on a baking sheet. Toast in oven until golden ⏱️ 2 minutes .
7. 7

   Spread béchamel onto buns, then fill with burgers and caramelized onion. Serve with kale chips on the side.