Lightly pound chicken to even thickness. Season both sides with salt, pepper, garlic powder, and Italian seasoning. Heat 2 tablespoons butter and 1 tablespoon olive oil in a large skillet over medium-high heat. Add chicken in a single layer. Cook 3 minutes, flip, and cook 2 to 4 minutes more, until cooked through. Transfer to a cutting board, cover with foil, and let rest.
In the same skillet, heat remaining 2 tablespoons olive oil over high heat. Add broccoli and cook 2 minutes. Add bell pepper, zucchini, and squash. Cook 2-3 minutes, until crisp-tender. Stir in peas, cherry tomatoes, garlic, and salt and pepper to taste (about 1/4 tsp each). Cook 1 to 2 minutes, just until tomatoes begin to soften.
Reduce heat to low. Push vegetables to the edges of the pan. Add remaining 5 tablespoons butter to the center. Once mostly melted, stir it through the vegetables. Pour in heavy cream. Add Parmesan, 1/4 cup at a time, stirring until fully melted and smooth.
Meanwhile, bring 12 cups water to a boil in a large pot. Add 1 tablespoon salt, then add pasta. Cook according to package directions, subtracting 1 minute. Reserve 1 cup pasta water, then drain.
Slice or dice the rested chicken. Add chicken and pasta to the skillet. Stir in 1/2 cup reserved pasta water, lemon zest, and 1 tablespoon lemon juice (add more to taste). Toss over medium heat 1 to 2 minutes, until sauce thickens and coats the pasta. Add more pasta water as needed to loosen.
Remove from heat. Taste and adjust salt if needed, then stir in basil. Divide into bowls, top with toasted pine nuts and extra Parmesan, and serve immediately.
Video
Notes
Note 1: Parmesan is key to the flavor. Don’t use canned or pre-grated cheese; it won’t melt smoothly or taste right. Use a block of cheese and grate it finely with a microplane. Gently pack it in measuring cup for accurate amount.Note 2: Use heavy cream for the best texture. Lighter cream or milk will not thicken the same way.Note 3: Add at the very end to keep it fresh and bright.Note 4: Toast in a dry skillet over medium heat for 2 to 3 minutes, stirring often, until lightly golden and fragrant. Watch closely so they do not burn.Storage: Best served right after tossing, when it’s extra creamy. Store leftovers in an airtight container in the fridge up to 3 days. Reheat gently with a splash of cream or broth. Freezing not recommended.