Add 12 oz dried spaghetti and cook uncovered, stirring occasionally, until al dente (check package for time, usually 8–10 minutes). Reserve 1 cup of pasta cooking water, then drain the pasta and set aside.

Sauce Base

Warm oil and butter

While the pasta cooks, heat a large wide skillet over medium heat. Add 3 tbsp olive oil and 2 tbsp butter. When the butter melts and begins to foam, add the sliced garlic and chopped shallot.

Sauté garlic and shallot for 1–2 minutes until fragrant and translucent but not browned. Add 1 tsp crushed red pepper flakes and 1 tsp lemon zest; cook 20–30 seconds to bloom the spices.

Deglaze the pan by adding 3 tbsp chicken or vegetable broth, scraping any browned bits from the bottom. Allow the liquid to reduce by half, about 1–2 minutes.

Reduce heat to low and stir in 1 cup heavy cream. Bring to a gentle simmer, then whisk in 3 oz grated Parmesan until melted and smooth. If the sauce seems too thick, add 2–4 tbsp reserved pasta water to loosen.

Proteins & Veg

Add 1 cup halved cherry tomatoes to the simmering sauce and cook 2 minutes until they start to soften.

Stir in 2 cups fresh baby spinach and cook just until wilted, about 1 minute.

If using cooked chicken, add 2 cups shredded or cubed chicken to the sauce and warm through for 2–3 minutes.

Combine & Finish

Add the drained pasta to the skillet with the sauce. Toss gently to combine, adding reserved pasta water by tablespoons as needed to achieve a silky, clingy sauce that coats the noodles (use 1/4–1/2 cup as necessary).

Stir in 2 tbsp fresh lemon juice, 1 cup chiffonaded basil, 1/2 tsp salt (adjust to taste), and 1/2 tsp freshly ground black pepper. Toss to combine and heat through for 1 minute.

Turn off the heat and finish with an extra 1 tbsp butter if desired for gloss. Taste and adjust seasoning. Serve immediately with extra Parmesan and lemon wedges on the side.