Turkey Smash Burgers with Balsamic Mushroom-Onion Pile

Steps

1. Prepare first: slice the mushrooms and onion, mince the garlic, slice the mozzarella and tomato, and dry the romaine leaves. Divide the ground turkey into 8 loose balls without packing them and keep them chilled.
2. Heat half the olive oil in a large cast-iron skillet over medium heat. Add the onion and cook, stirring often, for 10 minutes until soft and golden.
3. Add the mushrooms and thyme to the onion and cook 8 minutes until browned and their liquid has cooked off. Stir in the garlic for 30 seconds, then the balsamic and soy sauce, and cook 1 minute until glossy. Move the topping to a bowl and cover to keep warm; wipe out the skillet.
4. Arrange the romaine leaves and tomato slices on 4 plates as the base.
5. Heat the skillet over high heat until very hot and brush with the remaining half of the olive oil. Add 4 turkey balls, spaced apart, and smash each flat to about 1/4 inch with a sturdy spatula. Season the tops with half the salt and half the black pepper.
6. Cook 2 to 3 minutes until the edges are deeply browned and crisp, then flip, top each patty with a slice of mozzarella and cook 1 to 2 minutes more until the cheese melts and the turkey reaches 165°F (74°C). Move to the plates.
7. Repeat with the remaining 4 turkey balls, the remaining half of the salt and black pepper, and the remaining mozzarella.
8. Stack 2 patties on each plate over the romaine and tomato and pile the warm balsamic mushrooms and onions on top. Serve right away.