At the heart of this recipe is velouté, a rich white sauce made with chicken stock and thickened with cream. You will get a more flavorful sauce by poaching the chicken in a broth or stock that you already have on hand.
I have eliminated 2 T of butter from the original recipe by dry sautéing the mushrooms, which gives them a nice roasted flavor. I have also brought in an essential ingredient that was missing from the original recipe card: slivered almonds.
- 8 ounces (225 g) spaghetti, strands snapped in half
- 1 pound (450 g) chicken breast fillets
- 2 C chicken broth or water
- ½ pound (225 g) mushrooms, stemmed and sliced
- 4 T (50 g) butter
- ¼ C (35 g) all-purpose flour
- ½ C (120 mL) half-and-half
- ¾ t salt
- 2 T dry white wine
- 1 t thyme
- 2 T plus ¼ C grated Parmesan cheese (divided)
- ½ C slivered almonds, toasted
Preheat the oven to 450°F (225°C). Butter a 9×13 inch baking dish and set aside.
Cook the pasta in a large pot of boiling, salted water until tender but firm. Reserve ¼ cup cooking water, drain spaghetti, and return to pot with the reserved liquid.
Meanwhile, place the chicken fillets and broth in a shallow skillet with straight sides. Bring the broth to a simmer over high heat, then reduce the heat so that the liquid barely bubbles. Cover the pan with a lid and cook until the meat releases clear juices when pierced with a fork, about 8 to 12 minutes. Remove the meat, reserving the stock, and let it stand until cool enough to handle. Cut or shred the meat into bite-sized pieces, then cover to keep it warm.
Wipe out the skillet and heat it over medium-high heat. Add the mushrooms and cook, stirring constantly, until the mushrooms give up their liquid, 5 to 8 minutes. Set the sautéed mushrooms aside with the chicken.
To make the velouté, melt the butter in a saucepan over medium-low heat, then add the flour and whisk until smooth. Cook, whisking constantly, for 1 minute. Remove the pan from the heat. Slowly add the reserved chicken stock and whisk until smooth. Whisk in the half-and-half, then return the pan to the stove, increase the heat to medium and bring the mixture just to a simmer. Stir in the salt, wine, thyme and 2 tablespoons of Parmesan, whisking constantly until the sauce is thick and smooth. Adjust seasonings to taste.
Add sauce, chicken, and mushrooms to spaghetti and mix well. Turn mixture into the prepared baking dish, sprinkle evenly with the remaining Parmesan and the slivered almonds, and bake until almonds are brown and mixture is bubbly, 13 to 15 minutes. Serve immediately with plenty of freshly cracked black pepper.