Bring a large pot of salted water to a boil. Adjust rack to top position and preheat oven to 425 degrees. Wash and dry produce.

Cut broccoli into bite-size pieces if necessary. Thinly slice one lemon; quarter remaining lemon (for 4 servings, thinly slice two lemons; quarter remaining lemons). Peel and mince or grate garlic. Roughly chop parsley.

Toss broccoli on a baking sheet with a drizzle of oil, garlic powder, salt, and pepper. Roast on top rack until browned and tender, 15-20 minutes. TIP: If needed, cover broccoli with foil to keep warm until ready to serve.

Once water is boiling, add rigatoni to pot. Cook, stirring occasionally, until al dente, 9-11 minutes. Reserve ¼ cup pasta cooking water (½ cup for 4 servings), then drain.

Pat chicken* dry with paper towels; place between 2 large pieces of plastic wrap. Pound with a mallet or rolling pin until chicken is about ½ inch thick. Season all over with 1 tsp Italian Seasoning (2 tsp for 4 servings), salt, and pepper. (Be sure to measure the Italian Seasoning—we sent more!)

Heat a drizzle of oil in a large pan over medium-high heat. Add chicken; cook until browned and cooked through, 4-6 minutes per side.

Turn off heat; transfer to a cutting board. Wipe out pan and let cool slightly.

Heat a drizzle of oil in same pan over medium-high heat. Add lemon slices in a single layer; cook, stirring occasionally, until fragrant and lightly browned, 1-2 minutes. Transfer to a plate.

Add garlic to same pan and cook, stirring, until fragrant, 30-60 seconds.

Whisk in reserved pasta cooking water, cream sauce base, stock concentrate, Parmesan, and juice from two lemon wedges (four wedges for 4 servings). Cook, whisking, until slightly thickened, 2-4 minutes.

Reduce heat to medium low. Whisk in sour cream and 1 TBSP butter (2 TBSP for 4) until smooth.

Slice chicken crosswise. Add chicken to pan and toss to coat.

Divide drained rigatoni between shallow bowls; top with saucy chicken. Spoon any remaining sauce from pan over everything. Garnish with seared lemon slices and parsley.

Serve with roasted broccoli and remaining lemon wedges on the side.