Step 1

Prepare a medium-high (400°F to 475°F) gas or charcoal grill fire.

Step 2

Meanwhile, in a small bowl, combine the cheese, basil, mayonnaise, and mustard. Season to taste with salt and pepper.

Step 3

In a large bowl, gently combine the lamb with the garlic and onion powders, paprika, 1 tsp. salt, and 1 tsp. pepper. Form into 4 thin patties about 5-1/2 inches wide.

Step 4

Grill the burgers and onion slices, flipping once, until the burgers are cooked to your liking (145°F for medium) and the onions are tender, 4 to 5 minutes for the burgers, 8 to 9 minutes for the onions.

Step 5

Spread the bun tops with the blue cheese mixture, and serve the burgers on the buns topped with the onions.