Wash and dry all produce. Bring a large pot of salted water to a boil. Trim, then thinly slice scallions, keeping greens and whites separate. Dice tomatoes into 1/2-inch cubes. Cut lemon into wedges.

Heat 2 TBSP oil in a large pan over medium-high heat. Add scallion whites, sausage, and Italian seasoning. Cook, breaking up meat into pieces, until sausage is browned and cooked through, 3-5 minutes. Stir in tomatoes and cook until just softened, 1-2 minutes.

Once water boils, add ravioli to pot. Cook, stirring occasionally, until al dente, 4-5 minutes. Scoop out and reserve 1 cup ravioli cooking water, then carefully drain. TIP: Gently shake your strainer with the drained ravioli in it to remove as much moisture as possible.

Reduce heat under pan with sausage mixture to low, then add a squeeze of lemon juice, a splash of reserved ravioli cooking water, and stock concentrates. Give everything a stir, scraping up any browned bits on bottom of pan. Stir in sour cream and 2 TBSP butter. Season with salt and pepper.

Carefully stir ravioli into pan. TIP: Add more cooking water as needed to give sauce a loose consistency. Season with salt, pepper, and a squeeze or two of lemon juice to taste.

Divide ravioli mixture between bowls, then sprinkle with scallion greens. Serve any remaining lemon wedges on the side for squeezing over.