Add all the ingredient into a small mixing bowl and mix until well combined. Set aside.
Veggies
I used a mandolin to slice the tomatoes and 1/2 and onion but that’s optional. I just wanted nice uniform slices. Using a knife does the same thing. For the cucumber ribbons, I used a peeler which is the easiest way to get ribbons.
Burgers
Grate 1/2 of the red onion into a large mixing bowl. Then add the lamb, beef, salt, pepper, cumin, oregano, minced garlic, parsley, mint, feta cheese, egg and breadcrumbs and mix until well combined.
Split the mixture into 4 and shape each one into a round ball, then flatten to the size of your burger buns. Place on a hot fry pan and fry on each side for 4-5 minutes. Cover with a lid for the final 4-5 minutes once flipped over.
To assemble, brush your bread buns with olive oil and grill until golden.
Add some Dijon mustard on the bottom of each burger bun. Spread around. Then add some rocket, the burger patty, garlic yogurt sauce, tomato, onion and finish with the cucumber ribbons.
Video
Notes
Garlic yogurt sauceYou can make this a day ahead of time! In fact, if you make it a day ahead of time, the flavour intensifies and it’s even yummier!Hamburger Patties TemperatureWhen cooking the hamburger patties, make sure they reach at least 70C / 160F.