Bring a large pot of salted water to a boil. Wash and dry all produce. Trim and thinly slice scallions, separating whites from greens. Dice tomato. Cut lemon into wedges.

Heat a large drizzle of 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 and scallions are softened, 3-5 minutes. Stir in tomato and cook until just softened, 1-2 minutes. Turn off heat.

Once water is boiling, gently add ravioli to pot. Reduce heat to a simmer. Cook, stirring occasionally, until al dente and floating to the top, 4-5 minutes. Scoop out and reserve 1/2 cup ravioli cooking water (1 cup for 4 servings), then drain. TIP: Gently shake strainer with ravioli in it to remove as much moisture as possible.

Stir stock concentrate, a squeeze of lemon juice, and a small splash of reserved ravioli cooking water into pan with sausage mixture. Cook over low heat, scraping up any browned bits from bottom of pan, 1-2 minutes. Stir in sour cream and 1 TBSP butter (2 TBSP for 4 servings). Season with salt and pepper. TIP: Add more cooking water as needed until sauce reaches a creamy consistency.

Carefully stir ravioli into pan with sauce. Season with salt, pepper, and lemon juice to taste.

Divide ravioli mixture between bowls. Garnish with scallion greens. Serve with any remaining lemon wedges on the side.