Serves6 to 8
Prep time: 10 minutes
Cooking time: 20 minutes to 30 minutes
- 10 ounces cremini mushrooms
- 1/2 medium yellow onion
- 4 cloves garlic
- 1 ounce Parmesan cheese, grated (about 1/2 cup), plus more for serving
- 1 tablespoon freshly squeezed lemon juice
- 4 boneless, skinless chicken breasts (about 2 pounds total)
- 1/2 teaspoon kosher salt, plus more for seasoning
- 1/4 teaspoon freshly ground black pepper, plus more for seasoning
- 1 tablespoon olive oil
- 3 tablespoons unsalted butter
- 2 tablespoons all-purpose flour
- 1 cup half-and-half or whole milk
- 1/2 cup low-sodium chicken broth or water
- 4 ounces baby spinach (about 4 packed cups)
- Prepare the following and place together in a medium bowl: cut 10 ounces cremini mushrooms into 1/4-inch-thick slices, finely chop 1/2 medium yellow onion, and mince 4 garlic cloves.
- Grate 1 ounce Parmesan cheese (1/2 cup); set aside. Squeeze 1 tablespoon lemon juice into a small bowl or ramekin.
- Pound 4 boneless, skinless chicken breasts one at a time: Place 1 chicken breast in a gallon-sized zip-top bag and pound with a rolling pin or the flat side of a meat mallet to an even 1/2-inch thickness. Set aside and repeat with the remaining breasts. Pat the chicken dry with with paper towels. Generously season all over with kosher salt and black pepper.
- Heat 1 tablespoon olive oil in a 10-inch or larger skillet over medium-high until shimmering. Working in batches if needed, add the chicken and sear until deeply browned on the bottom, 5 to 7 minutes. Flip and sear the other side until browned, 5 to 7 minutes. Transfer the chicken to a plate; set aside.
- Reduce the heat to medium and melt 3 tablespoons unsalted butter in the skillet. Add the mushrooms, onion, garlic, 1/2 teaspoon kosher salt, and 1/4 teaspoon black pepper, and cook, stirring occasionally, until the vegetables are tender, 3 to 5 minutes. Sprinkle with 2 tablespoons flour, stir to evenly coat the vegetables, and cook for 1 minute.
- Add 1 cup half-and-half or whole milk and 1/2 cup low-sodium chicken broth or water, and stir until no lumps from the flour remain, making sure to scrape up any browned bits from the bottom of the pan. Bring to a boil. Reduce the heat to a simmer and stir in 4 ounces baby spinach (about 4 packed cups) and the Parmesan cheese until the spinach just begins to wilt, about 30 seconds.
- Return the chicken to the pan and simmer gently until the sauce is thickened enough that it coats the back of a spoon and the chicken is cooked through, 3 to 4 minutes. Stir the lemon juice into the sauce and serve immediately, garnished with more Parmesan, if desired.