How to Make the Best California Burger Gelson's

Ingredients

• ½ cup mayonnaise
• ¼ cup ketchup
• 1 tsp sweet pickle relish
• 1 tsp Dijon mustard
• 1 tsp white wine vinegar
• Kosher salt, to taste
• Black pepper, to taste
• 2 lb Gelson's fresh Certified Angus Beef® brand 80/20 ground beef
• 2 Tbsp grapeseed oil, divided
• 6 slices white cheddar cheese
• 6 tsp butter, room temperature, divided
• 6 soft hamburger buns
• 2 tomatoes, sliced
• 2 oz alfalfa sprouts
• 1 red onion, sliced
• 1 avocado, seeded and sliced