El Perro Negro - Tallegio + black truffle mayo burger

El Perro Negro based in Glasgow is another one of the finalist of the National Burger Awards in 2019 take a look at their recipe.

For the truffle mayo:
- In a large bowl add all the ingredients and mix all the ingredients thoroughly .
- Chill until required.
For the caramelised onion:
- Peel and slice the onions thinly.
- Cook the onions in a heavy bottomed pan on a medium heat
- Add a touch of vegetable oil andhalf of the unsalted butter, wait until melted
- Add the onions and season with salt to sweat
- Keep moving the onions until they start to colour and stick to the pan
- Add the remaining 100g of butter and continue until the onions are dark and glossy
For the burger:
- Get your butcher to mince both the fat and the meat together in a medium grind, passed through twice, thenshape into 150g patties.
- Get a frying pan hot then season each side of the burgers generously with salt and place in the pan.
- Cook for 4 minutes on one side ensuring it has a nice brown crust on.
- Flip over and do the same to the other side and continue to cook for a further 4 minutes.
- Once there is a nice crust on both sides flip every 20 seconds to ensure its evenly cooked.
For assembly:
- Whilst the burgers are still in the pan, place a nice slice (or two) of tallegio cheese
- Then add the hot caramelised onions, this should help melt the tallegio cheese on both sides
- Place the burgers down on the bottom half of bun (ideally toasted), on the other half put a generous dollop of the truffle mayo and place on top of the burger