Heat a large drizzle of olive oil in a large pot over medium heat. Add tomato paste, Italian Seasoning, garlic powder, stock concentrate, and chili flakes to taste (we used ⅛ tsp; ¼ tsp for 4 servings). Cook, stirring, until fragrant and tomato paste darkens in color, 30-60 seconds. 

Whisk cream cheese into pot with sauce mixture. Cook, whisking, until melted and combined, 20-30 seconds.

Wash and dry produce.

Stir rigatoni and 2 1/4 cups water (3 1/2 cups water for 4 servings) into pot with sauce mixture; season with salt and pepper. (TIP: Gently separate rigatoni with your hands before adding to pot.) Increase heat to medium-high and bring to a simmer.

Cook, stirring constantly, until rigatoni is tender and sauce is creamy and thickened, 5-6 minutes. (TIP: Gently scrape rigatoni from bottom of pot if it begins to stick.) Remove from heat.

Add spinach and stir until wilted, 30-60 seconds. TIP: Depending on the size of your pan, you may need to add spinach in batches––stir in a splash of water to help spinach wilt if needed.

Tear mozzarella into bite-size pieces and sprinkle evenly over pasta. Season with salt and pepper.

Divide pasta between shallow bowls or serve family style with any remaining chili flakes on the side.