Add the egg yolks, ground cumin, salt, sriracha, and Dijon mustard to a food processor. Start pulsing the food processor and slowly stream in the canola oil. Spoon the mayo mixture into a separate bowl, and fold in the lemon juice. Set aside in the fridge if not immediately using.

Shortcut option: Mix 3/4 cup (180ml) store-bought mayonnaise with 2 tablespoons (30ml) lemon juice, 1 tablespoon ground cumin, 1/2 teaspoon salt, 1 teaspoon sriracha, and 1 teaspoon Dijon mustard.

First, make the burger patties by mixing the ground lamb, salt, pepper, paprika, and ground cumin.

Form into 4 patties, set on a plate and loosely drape a piece of plastic wrap on top. I suggest letting it rest in the fridge for at least 8 hours, or up to 24 hours, to intensify the flavours seriously.

Make the cumin mayo.

Make the caramelized onions — In a large skillet, drizzle with olive oil, add the sliced red and yellow onion. Sprinkle with salt, and drizzle with a little more olive oil on top; toss to make sure all the onions are coated with olive oil. Cook at medium-low heat for about 20 to 30 minutes. Set aside.

Preheat grill to medium-high heat (400-450°F / 200-230°C). Toast the brioche buns on the grill. Set aside. Grill the lamb burger patties over medium-high heat for about 4-5 minutes per side for medium doneness (internal temperature of 145°F / 63°C). Lamb can be served medium — do not press down on patties while grilling or you will squeeze out the juices. Add crumbled feta on top of the burgers during the last minute of grilling so it softens slightly from the residual heat.

Spread the cumin mayo on the bottom of the toasted brioche bun, add the lamb topped with feta, caramelized onion, a small handful of arugula, and the top of the bun that has more cumin mayo spread on it.