1 pound 80/20 ground chuck
1. Remove the stems and scrape out the gills. Set aside.
2. In a bowl, add in balsamic vinegar, olive oil, dried basil and sugar. Whisk all of the ingredients together.
3. Place the mushrooms in a large Ziploc bag and pour in the marinade. Zip the bag and place in the refrigerator for 2-3 hours or overnight.
1. Preheat the oven to 375°F.
2. Lay out 2 long strips of 12" wide aluminum foil, and place the potatoes in the middle of the foil. Drizzle olive oil directly on top of the potatoes. Add chopped garlic and season to taste.
3. Wrap the potatoes in a tent of foil, leaving space for the potatoes to steam, and place them in the oven for 20-25 minutes.
1. Set the grill temperature or bring it up to 400°F.
2. Form the patty into two thick 8 oz. patties. Pack the patties tightly to hold their shape. Season on both sides with salt and pepper to taste. Heavier seasoning on pepper is a must.
3. Brush the sweet onions with olive oil to help them caramelize and get grill marks. Season with salt and pepper to taste.
4. Remove the marinated mushrooms from the Ziploc bag and season with salt and pepper. Save the marinade.
5. Place both patties on the grill, grill for 5-6 minutes, and then flip the patties. After flipping the burgers, grill the onions and mushrooms, flipping the mushrooms after 3 minutes. Grill the hamburger buns. After 5-6 minutes, take everything off of the grill.
1. Let the patties rest for 10 minutes.
2. Take the potatoes out of the oven and place them in a bowl. Garnish with fresh rosemary.
3. Lay down the toasted buns. Stack 1 patty, 2 slices of Swiss cheese, grilled onion, 2 marinated mushrooms, tomato slices, and lettuce.
Serve and enjoy!