Ingredients
4 boneless, skinless chicken breasts (about 2 to 2 1/2 pounds total)
1 teaspoon kosher salt, divided
1/2 teaspoon black pepper, divided
1 1/2 cups heavy cream
1 cup finely grated Parmesan cheese (plus 2 tablespoons extra for topping, optional)
1 1/2 cups chopped fresh spinach (lightly packed) or 1 cup thawed frozen spinach, well squeezed dry
3 cloves garlic, minced
1/4 teaspoon ground nutmeg
1/2 teaspoon Italian seasoning (optional but nice)
1 tablespoon olive oil or softened butter (for greasing the glass casserole dish)
1 tablespoon chopped fresh parsley or extra spinach for garnish (optional)
Directions
Preheat your oven to 400°F (200°C). Lightly grease a glass casserole dish (about 9×13 inches) with olive oil or butter so the chicken doesn’t stick and cleanup is easier.
Pat the chicken breasts dry with paper towels so they sear and bake better instead of steaming. Season both sides of the chicken with about 1/2 teaspoon of the salt and 1/4 teaspoon of the black pepper.
Arrange the seasoned chicken breasts in a single layer in the greased glass casserole dish, leaving a little space between each piece so the creamy mixture can flow around them.
In a medium mixing bowl, whisk together the heavy cream, grated Parmesan, chopped spinach, minced garlic, ground nutmeg, Italian seasoning (if using), and the remaining 1/2 teaspoon salt and 1/4 teaspoon black pepper. Whisk until the mixture looks smooth, slightly thick, and the spinach and garlic are evenly distributed—this is your one velvety mixture.
Carefully pour this velvety cream, Parmesan, spinach, and garlic mixture evenly over the raw chicken breasts in the glass casserole dish, making sure each piece is well coated and there’s sauce pooling around them. If some spinach clumps on top of one piece, just nudge it around with a spoon.
If you like an extra cheesy top, sprinkle the additional 2 tablespoons of Parmesan evenly over the surface. This will help create a lightly golden, savory layer as it bakes.
Cover the glass casserole dish loosely with foil (tent it so it doesn’t stick to the sauce) and bake in the preheated oven for 20 minutes. Covering helps the chicken cook gently and keeps the sauce from reducing too quickly.
After 20 minutes, remove the foil and continue baking, uncovered, for another 10 to 20 minutes, or until the chicken is cooked through (the thickest part should reach 165°F/74°C) and the cream mixture is bubbling and slightly thickened around the edges. Total bake time is usually 30 to 40 minutes, depending on the thickness of your chicken breasts.
Once baked, let the casserole rest on the counter for about 5 to 10 minutes. The sauce will thicken a bit more as it cools slightly, making it perfect for spooning over sides. Taste a little of the sauce and add a pinch more salt or pepper if you think it needs it.
Sprinkle with chopped fresh parsley or a little extra chopped spinach for color, then spoon the creamy spinach Parmesan sauce over the chicken as you serve. Serve straight from the glass casserole dish with your favorite cozy sides.
Variations & Tips
For meal prep, you can assemble the whole dish ahead: season the chicken, pour the velvety cream-Parmesan-spinach mixture over it in the glass casserole dish, cover tightly, and refrigerate up to 12 hours before baking. If baking straight from the fridge, add 5 to 10 extra minutes and check for doneness. To lighten it up a bit, swap half of the heavy cream for half-and-half; the sauce will be slightly thinner but still comforting. If you prefer dark meat, use boneless, skinless chicken thighs and start checking for doneness around 25 minutes—they stay very tender in the creamy sauce. For extra veggies, stir in a handful of thawed, well-drained frozen peas or a few chopped sun-dried tomatoes into the velvety mixture before pouring it over the chicken. If you like a little kick, add a pinch of red pepper flakes with the nutmeg. To make it more casserole-style, slice the cooked chicken and toss it back into the sauce with cooked pasta or rice right in the glass dish, then top with extra Parmesan and broil for a couple of minutes until lightly golden. Leftovers reheat well in the microwave or covered in the oven at 300°F; if the sauce thickens too much, stir in a splash of milk or cream to loosen it.