Classic Beef Burgers

Ingredients

• 3/4 lb. ground beef chuck
• 3/4 lb. ground beef sirloin
• 1 tsp. sea salt
• 1/2 tsp. freshly ground pepper
• 1/2 cup mayonnaise
• 1/2 tsp. fresh lemon juice
• 1/4 tsp. finely chopped fresh thyme
• 1/4 tsp. snipped fresh chives
• 1/4 tsp. finely chopped fresh basil
• Sea salt and freshly ground pepper, to taste
• 4 brioche buns, split
• 2 heirloom tomatoes, sliced 1/4 inch thick
• 2 avocados, peeled, pitted and sliced
• 4 Boston lettuce leaves
• 4 thin red onion slices (optional)
• 1 focaccia bread slab, about 6 inches square
• 2 Maui onions, sliced 1/2 inch thick
• 1/4 cup olive oil
• 1/2 lb. Gorgonzola cheese
• 4 slices Vermont cheddar cheese
• 1/2 cup barbecue sauce
• 4 Kaiser rolls, split
• 8 bacon slices, cooked