Start by making a roux. Melt 2 tablespoons of butter in a saucepan, add 2 tablespoons of flour and whisk over medium heat for about a minute. Whisk in the cream and chicken stock. Add salt, pepper, paprika, parmesan cheese and balsamic vinegar. Remove from heat and set aside.
Add 2 tablespoons of butter to a large pan and melt over medium high heat. Add the finely diced onion. Cook, stirring occasionally until translucent. Add garlic, mushrooms and thyme and cook until everything is softened, making sure to stir so nothing burns. Add in spinach and stir until wilted. Remove from heat, add gouda. Stir everything together to distribute the ingredients and melt the cheese. Set aside.
Preheat oven to 350F
Slice the chicken breast into a thin strip so it can be stuffed. Pound the breast until tender and thin. Add filling to the breast and fold to enclose. (You should have a good amount of sauce left over for later) You can seal the breast using toothpicks so it holds together in the next step but they’re optional. You can also season the outside with salt and pepper.
Add the butter or oil to a pan over high heat. Add the breasts and sear for a 2-3 minutes on each side.
Transfer breasts to a baking dish and spoon some of the sauce on top of each breast.
Bake at 350F for about 25 minutes. Increase temperature to broil and bake 4 minutes longer. Remove from oven.
I recommend serving with rice or pasta mixed with the remaining filling and sauce. If you’re curious I paired this with asparagus spears and was quite content. Hope you enjoy!
If you want to make a vegetarian version, just serve the amazing sauce with some pasta!