Made with spicy sausages and smoky grilled onion, these are not your standard burgers.

4 oil-packed sun-dried tomatoes, drained
1/2 cup mayonnaise
1 tablespoon whole-grain Dijon mustard
8 ounces andouille sausages,* cut into 1-inch pieces
2 1/2 pounds ground beef (15% fat)
2 large shallots, minced
2 teaspoons salt
2 teaspoons ground black pepper
1 teaspoon fennel seeds, crushed

6 large sesame-seed hamburger buns
6 1/3-inch-thick slices red onion
Olive oil
1 cup coarsely grated Asiago cheese**

1 7- to 7 1/2-ounce jar roasted red peppers, drained

Finely chop sun-dried tomatoes in processor. Blend in mayonnaise and mustard. Transfer to small bowl.
(Can be made 1 day ahead. Cover; chill.)
Finely chop andouille sausages in processor. Transfer to large bowl.
Add beef, shallots, salt, pepper, and crushed fennel seeds.
Stir with fork just until blended. Form mixture into six 1-inch-thick patties.

Prepare barbecue (medium-high heat). Grill hamburger buns until golden, about 2 minutes.
Transfer to platter. Brush onion slices with oil. Sprinkle with salt and pepper.
Grill until golden, about 7 minutes per side. Grill hamburgers to desired doneness,
about 5 minutes per side for medium-rare. Sprinkle cheese over top of burgers.

Spread cut sides of hamburger buns with sun-dried-tomato mayonnaise.
Top bottom halves of buns with hamburgers, then red peppers.
Top with onion slices. Cover with top halves of buns and serve.

*Smoked pork-and-beef sausages, sold at specialty foods stores and supermarkets.
Kielbasa can be substituted.

Makes 6 servings.