In a bowl, mix the mayonnaise with the Greek yoghurt, mustard, lemon juice and grated Grana Padano until smooth. Add the salt and pepper to taste and leave to set in the fridge.
STEP 2
In a large bowl, season the ground beef with salt, pepper and a drizzle of extra virgin olive oil. Divide the mixture into four parts and form into hamburgers.
STEP 3
Wash the tomato, then slice it thinly, cut the red onion in the same way. Wash and dry the lettuce leaves. Set everything aside and prepare for cooking and assembly..
STEP 4
Heat a non-stick griddle or frying pan and cook the burgers for about 3-4 minutes per side, depending on the desired level of doneness. Cut the buns in half and toast them lightly in the same pan as the meat.
STEP 5
Spread the base of the bun with the Grana Padano sauce, add the lettuce, tomato, onion and freshly cooked hamburger. Top with the Grana Padano PDO Riserva flakes and finish with the top of the bun.