Created by breezermom on October 29, 2017
Step 1: Pickles:
Step 2: Combine the vinegar, dill, salt, and cucumber in a large sip-top plastic bag or jar; seal. Turn bag until the ingredients are well combined.
Step 3: Refrigerate at least an hour, turning bag or shaking the jar occasionally.
Step 4: Burgers:
Step 5: Place the cremini and button mushrooms in the bowl of a food processor; pulse 4 to 5 times or until coarsely chopped.
Step 6: Heat a large skillet over medium-high heat. Add the oil to the pan; swirl to vcoat. Add the onion and garlic; sauce 3 minutes.
Step 7: Add the mushrooms, 1/4 teaspoon salt, and 1/8 teaspoon black pepper to the pan; cook 7 to 10 minutes or until the liquid evaporates, stirring occasionally.
Step 8: Remove the pan from the heat; cool mushroom mixture completely.
Step 9: Place the beef in a bowl. Add the cooled mushroom mixture to the beef; stir just until combined. Refrigerate for 10 minutes. Shape the beef mixture into 4 patties. Sprinkle evenly with the remaining 1/4 teaspoon salt and remaining 1/8 teaspoon pepper.
Step 10: Heat a large cast-iron skillet over medium-high heat. Coat the pan with cooking spray. Add the patties to the pan; cook 2 minutes on each side or until they have reached your desired degree of doneness.
Step 11: Combine the mayonnaise, ketchup, and mustard in a small bowl, stirring with a whisk. Spread the mixture evenly over the bottom and top of the toasted buns. Place 4 pickle slices on the bottom half of each bun. Top evenly with the patties, and if desired, the lettuce, tomato and onions. Top with the top half of the bun.