My House Hamburger with Pickled Red Onions, Dijon Mayonnaise, and Shredded Romaine in a Ciabatta Bun

• 2 1/2 pounds best-quality ground beef
• 1 1/2 teaspoons kosher salt
• 1 large egg
• 2 teaspoons Dijon mustard
• 1/2 teaspoon fresh lemon juice
• 1/2 teaspoon kosher salt
• 1/2 cup extra virgin olive oil
• 1/2 cup peanut oil
• 1 large red onion, sliced into thin rounds
• 1/4 teaspoon kosher salt
• 2 tablespoons red wine vinegar
• 2 tablespoons water
• 1 tablespoon sugar
• Extra virgin olive oil, if cooking in a skillet
• 6 mini ciabatta or other buns, split
• 3 cups shredded romaine lettuce leaves

1. Place the beef in a medium bowl, sprinkle with the salt, and lightly mix with your hands until thoroughly blended.
2. Cover and refrigerate for at least 4 hours or up to overnight.
3. To make the mayonnaise, in a food processor, combine the egg, mustard, lemon juice, and salt and process until thoroughly blended.
4. With the motor running, slowly drizzle in the oils to make a thick emulsion.
5. Transfer to a small bowl, cover, and refrigerate until ready to use or for up to 5 days.
6. To make the pickled onions, toss together the onions and salt in a medium bowl.
7. Combine the vinegar, water, and sugar in a small saucepan and bring to a boil, stirring to dissolve the sugar.
8. Pour the hot mixture over the onions, stir well, and set aside for at least 1 hour or up to overnight.
9. To cook the burgers, prepare a medium-hot grill or film a large, heavy skillet, preferably cast iron, with oil and place over medium-high heat.
10. Divide the ground beef into 6 equal portions, and form each portion into a patty about 1/2 inch thick.
11. Place the patties on the grill directly over the heat source or in the hot skillet.
12. Cook, turning 2 or 3 times, until medium-rare, about 9 minutes, by either method, or until as done as you like.
13. Toast the ciabatta, cut sides down, on the grill or cut sides up in a toaster oven for 1 to 2 minutes until beginning to turn golden.
14. Sandwich a patty between bun halves and serve at once.
15. Pass the mayonnaise, pickled onions, and lettuce on the side to be added as desired.

ground beef, kosher salt, egg, mustard, lemon juice, kosher salt, extra virgin olive oil, peanut oil, red onion, kosher salt, red wine vinegar, water, sugar, extra virgin olive oil, buns, shredded romaine lettuce leaves

Taken from www.epicurious.com/recipes/food/views/my-house-hamburger-with-pickled-red-onions-dijon-mayonnaise-and-shredded-romaine-in-a-ciabatta-bun-389514 (may not work)