Preheat an oven to 450°F. Line two baking sheets with parchment paper.

Cut off the florets from both heads of cauliflower. Try removing as much of the stalk from the florets as possible.

Place some of the florets in a food chopper or food processor. Pulse about three to four times to produce cauliflower rice size. Repeat with additional cauliflower florets until you have 6 cups or just over of cauliflower rice.

Place the cauliflower rice in a large microwave safe bowl. Microwave on high for 8 to 9 minutes or until cooked and tender.

Transfer the cooked cauliflower rice to a cheesecloth or tea towel. Twist around the cauliflower rice and place in the refrigerator until cool enough to handle. Once cooled, about 5 minutes, twist and squeeze to release as much liquid as possible.

Combine the cooked cauliflower rice, shredded mozzarella, eggs, and salt in a bowl. Gently stir to combine.

Equally divide the mixture into 4 sections on each baking sheet. Shape into equal size squares about 1/4-inch thick. Bake for 16 minutes. Allow cooling for 10 minutes. Use immediately or store in a zip top bag and store in the refrigerator until ready to use.

For the caramelized onions, heat a large sauté pan over medium heat. Add the oil and butter.

While the butter is melting, halve the onion and remove the skin. Cut into about ¼-inch thick slices. Add to the pan and cook for 10 minutes. Toss. Cook for another 20 minutes, tossing occasionally.

Combine the ground round, salt, black pepper, and Worcestershire sauce in a medium bowl. Gently fold to incorporate the ingredients.

Divide the patties into 4 equal sizes about 1/2-inch thick.

Heat a large nonstick sauté pan over medium-to-medium high heat. Add the patties to the pan. Cook for 4 minutes, flip the patties over and cook for another 2 minutes. Reduce the heat to medium and cook for another 2 minutes.

To assemble, place a piece of cheddar cheese on top of one slice of the cauliflower crust and mozzarella cheese on the other slice. Place a patty on one half. Top with some of the onions and then the other cauliflower crust half.

Heat a large nonstick sauté pan over medium to medium-high heat. Add two of the patty melts to the pan. Cover and cook for about a minute. Flip the patty melt over, cover and cook for another minute or two or until the cheese has melted.

Repeat with the additional patty melts.

Recipe by Whitney Miller on behalf of  the Vidalia® Onion Committee