Slice the chicken into 1-inch thick cutlets, then season both sides generously with Italian seasoning, kosher salt, and freshly ground black pepper. Let the seasoned chicken sit at room temperature for 5-10 minutes while you prepare the remaining ingredients—this allows the seasoning to adhere better. Slice the mushrooms into 1/4-inch thick pieces, mince the garlic cloves, remove the stems from the spinach, and grate the parmesan cheese fresh. Having everything prepped and ready will make the cooking process smooth and help you build flavors efficiently.

Heat 1.5 tablespoons of olive oil in a large skillet over medium-high heat until shimmering. Once hot, carefully lay the seasoned chicken cutlets in the pan without moving them—this creates a golden crust through proper searing. Cook for 12-15 minutes on the first side until golden brown, then flip and cook for another 12-15 minutes on the second side until cooked through. Transfer the chicken to a clean plate and set aside; don't worry if it's not fully cooked through, as it will finish cooking when added back to the sauce.

In the same skillet with the browned bits remaining from the chicken, add 2 tablespoons of olive oil over medium-high heat. Add the sliced mushrooms and let them cook undisturbed for 2-3 minutes until they begin to brown and release their moisture—I like to avoid stirring too early because it allows the mushrooms to develop deeper flavor through browning. Then stir and cook for another minute before adding the minced garlic, cooking for exactly 1 minute until fragrant but not browned.

While the garlic is cooking, whisk together the almond milk and gluten-free flour in a small bowl or measuring cup until completely smooth with no lumps—this prevents the flour from clumping when it hits the hot pan. Pour this mixture into the skillet with the mushrooms and garlic, stirring constantly to combine. Continue cooking over medium heat for 1-2 minutes, stirring frequently, until the sauce begins to thicken slightly. The flour will absorb liquid and create a light, creamy base for the spinach and parmesan.

Reduce the heat to medium-low and add the stemmed spinach and freshly grated parmesan cheese to the pan, stirring gently until the spinach begins to wilt. Continue stirring for 2-3 minutes until the spinach is completely wilted and the cheese has melted into the sauce, creating a smooth, creamy consistency. Sprinkle in the crushed red pepper flakes and stir to incorporate. The sauce should coat the back of a spoon but still be pourable—if it seems too thick, add a splash more almond milk.

Gently nestle the seared chicken cutlets from Step 2 back into the creamy spinach sauce, turning them to coat both sides. Cook over medium-low heat for 1 minute, just until the chicken is heated through and fully incorporated into the dish. Transfer to serving plates or a platter, spooning the sauce and wilted spinach over and around the chicken. Serve immediately while the sauce is still warm and creamy.