French onion burger

Small dice a thousand grams of yellow onions: slice a half onion four or five times latitudinally, turn 90 degrees and chop roughly longitudinally.

Combine the onions with about five grams of salt, a long squeeze of olive oil and about 150 grams of water in a pan.

Simmer about 10 minutes without stirring, until the water has evaporated and the onions are mostly soft.

Drop to medium heat and caramelize about 20 minutes, stirring every five minutes.

Stir in the red wine vinegar and cook until it evaporates; the onions should be candy sweet and purpley brown. Cool completely.

Cook the patty as before, flip, and lay on one slice of Gruyere and one slice of Provolone.

Slide the pan into the oven under a hot broiler for about 20 to 25 seconds, until the cheese bubbles and fries around the patty.

Build: Dijon style mustard on the bottom bun, a few tablespoons of room temperature caramelized onions, the fried cheese patty, mayo on the top bun.