1/2 tsp cumin seeds
1/2 tsp coriander seeds
1/2 c mayonnaise
2 tbsp extra-virgin olive oil plus additional for brushing
2 tsp fresh lemon juice
1-1/2 tsp smoked paprika
1 garlic clove, pressed
1 lb GROUND DARK-MEAT TURKEY
4 (1/3-Inch thick) red onion slices
1 Large red bell pepper, qtered and seeds removed
4 Slices white Cheddar cheese
4 Crusty hamburger buns, split and toasted
Arugula leaves As needed
Pickle wedges As needed
Toast cumin and coriander seeds in skillet over medium-high heat until aromatic and slightly darker in color, shaking skillet often, about 1-1/2 minutes. Cool. Finely grind toasted seeds in spice grinder or in mortar with pestle.
Whisk together mayonnaise, 2 tablespoons olive oil, lemon juice, paprika, garlic, and ground spices. Season aioli to taste with salt and pepper.
In a medium bowl, gently mix turkey with 2 tablespoons aioli. Using damp hands, divide turkey mixture into 4-ounce portions, forming each into scant 3/4-inch thick patty, about 3-1/2 inches in diameter. Using thumb, make small indentation in center of each burger.
Preheat grill to medium-high heat.
Brush onion slices and bell pepper pieces with oil and sprinkle with salt and pepper. Grill onions and bell peppers until soft and charred, about 4 minutes per side. Hold for service.
Sprinkle burgers with salt and pepper. Grill turkey burgers 5 minutes. Turn over; grill until almost cooked through, about 4 minutes. Top each burger with 1 cheese slice and grill until turkey is cooked through, the internal temperature reaches 165 degrees F and cheese melts, about 1 minute longer. Place turkey burger on the bottom of the bun.
Arrange grilled red pepper pieces, then grilled red onion slices over. Top each with dollop of aioli and arugula.
Cover burgers with bun tops and serve with pickle wedges.