Smash Burger

Add all the ingredients to a bowl and stir to combine. If you can't find relish, you can substitute it with finely chopped pickled cucumbers. If you don't have lemon juice or want a tangier flavour, then substitute the lemon juice with apple cider vinegar.

To get the best hamburger patties, try to buy beef with a high fat content, ideally around 20% fat. Divide the meat into 8 servings of 100 grams. Flatten each portion, so it reaches a diameter of 10 cm. If they have the right weight and diameter, they will also have the desired thickness. Which is important to ensure they are cooked just right. When the patties are 10 cm wide, you can fit 4 in the 28 cm pan and 3 in the 24 cm pan. You can also flatten the patties between two pieces of baking parchment. And you can prepare the patties in advance, just keep them in the fridge or freezer until you need them. Season the patties with salt.

Melt the butter in a frying pan at 175ºC. Briefly place the buns cut-side down to soak up some of the butter. After a few seconds, flip them so they do not absorb it all. Toast the buns for 2 minutes on the crust side. Turn them over and then toast the cut side for 2 minutes.

Use the same pan as the buns were toasted in but increase the temperature to 220ºC. Place each patty directly on top of a small dollop of butter. A little under a teaspoon. The butter helps to brown and give flavour to the meat and ensures a nice sear. The patties should cook for 4 minutes in total. 2 minutes on each side. Add a slice of cheese to each patty for the last minute. If you prefer very melted cheese, then cover with a lid for the last ½-1 minute.

Peel the onion and dice it finely. Wash the tomatoes and cut them into slices. Spread some sauce on the bottom bun and add some chopped onion. Then add two patties and tomato slices. Finish with the top bun.