Caramelize the onion. Melt the 2 tablespoons butter in a Dutch oven or large cooking pot over medium-low heat. Add the 1 cup finely diced onion and cook for approximately 10 minutes, stirring from time to time. Continue until the onion becomes translucent and develops a light golden-brown color.

Cook the garlic and sun-dried tomatoes. Add the 7 minced garlic cloves and 3 ounces chopped sun-dried tomatoes to the softened onion. Sauté for 3–4 minutes, stirring occasionally, until the garlic becomes fragrant and the tomatoes soften slightly.

Deglaze with white wine. Increase the burner to medium heat and pour in the 3/4 cup dry white wine. Scrape the bottom of the pot with a spatula to loosen and incorporate any browned pieces. Allow the wine to simmer briefly so that it reduces slightly and its flavor becomes more concentrated.

Simmer the chicken soup. Stir in the 4 cups shredded cooked chicken, 1 teaspoon Italian seasoning, 1 teaspoon garlic powder, 1 teaspoon onion powder, 1/2 teaspoon garlic salt, 1/2 teaspoon paprika, and 32 ounces chicken broth. Increase the heat to medium-high and bring the mixture to a simmer. Cook uncovered for about 10 minutes, allowing the flavors to combine and the broth to reduce slightly.

Add the creamy finishing ingredients. Remove the pot from the heat. Stir in the 1/2 cup heavy whipping cream, 1/2 cup grated Parmesan, and 2 cups finely chopped spinach. Continue stirring until the Parmesan has melted smoothly into the soup and the spinach has wilted.

Rest before serving. Allow the finished soup to stand for a few minutes before serving so the flavors can settle and blend fully.