- 1/2 cup mayonnaise
- 1 1/2 tablespoons Dijon mustard
- 2 tablespoons minced chipotle in adobo, including some sauce, divided
- 8 bacon slices
- 1 1/2 pounds ground beef chuck (not lean)
- 2 teaspoons sweet smoked paprika
- 1 large red onion, cut into 4 (1/2-inch) thick rounds, each stuck with a wooden pick to keep it together
- 1 firm-ripe avocado, quartered lengthwise, peeled, and cut lengthwise into 1/3-inch thick slices
- Olive oil for brushing on onion and avocado
- 4 hamburger buns, grilled or toasted
- lettuce; cilantro sprigs
- instant-read thermometer
- In a food processor or blender, purée mayonnaise, mustard, and 1 tablespoon chipotle; transfer to a bowl.
- Cook bacon in batches in a skillet over medium heat, turning occasionally, until crisp; transfer to paper towels to drain.
- Gently mix beef with 1 tablespoon chipotle, paprika, and 1 teaspoon salt until combined. Form into 4 (4-inch) patties.
- Prepare a grill for direct-heat cooking over medium-hot charcoal (medium heat for gas).
- Meanwhile, brush both sides of onion rounds and avocado slices with olive oil.
- Oil grill rack then grill onion rounds, turning over once, until slightly charred, 2 to 3 minutes total. Discard wooden picks.
- Grill avocado slices, turning once, until grill marks appear, about 30 seconds on each side.
- Grill patties, covered only if using a gas grill, until they reach 160°F on an instant-read thermometer, approximately 5 to 6 minutes on each side.
- Put sauce on buns and make burgers with lettuce, avocado, bacon, onion, and cilantro.