Yapp Smash Burger with Mustard Onion Jam

Method

1. Thinly slice the onion. Heat half the oil in a 20 cm pan over medium-low heat and cook the onion for 18 min until soft and deep brown. In the last 2 minutes, add the brown sugar, vinegar and half the mustard and reduce to a sticky jam.

   Add in this stepVegetable oil 1 tspOnion 1Brown sugar 2 tspWhite vinegar 2 tspDijon mustard 1 tsp

   medium-low heat

2. Mince the garlic and parsley very finely and mix with the mayonnaise, the rest of the mustard and the lime juice to make the rof mayo.

   Add in this stepGarlic cloves 1Flat-leaf parsley 6 gMayonnaise 2 tbspDijon mustard 1 tspLime ½

3. Divide the beef into 4 portions of 60 g and roll them lightly into balls. Don't overwork them, keep them in the fridge until you cook them, and don't salt them yet.

   Add in this stepMinced beef (about 20% fat) 240 g

4. Halve the buns, butter the cut sides and toast them face down in a pan over medium heat for 1 min until golden.

   Add in this stepBurger buns 2Butter 10 g

   medium heat

5. Heat a 28 cm · 2× cast-iron or heavy pan over high heat for 2 min until very hot. Add the remaining oil, put the balls in, cooking in the batches shown, and immediately press each one flat to 5 mm with a wide spatula. Season with salt and pepper and cook untouched for 2 min until the edges are dark and crisp, then flip and cook for 30 seconds more. They must be cooked through with no pink inside.

   Add in this stepVegetable oil 1 tspSalt ½ tspGround black pepper ½ tsp

   high heat

6. Spread rof mayo on the bottom buns, then add lettuce, two patties and onion jam, put the tops on and serve straight away.

   Add in this stepRomaine lettuce 30 g