Peel and finely chop the onion and garlic; slice the sun-dried tomatoes into thin strips if not already julienned.
Heat a large deep skillet over medium-high heat and add the 3 tablespoons of oil from the sun-dried tomato jar.
Add the chopped onion and cook for 3–4 minutes until softened, then add the garlic and cook for about 30 seconds until fragrant.
Sprinkle the 2 tablespoons of flour over the onions and stir to coat the vegetables, cooking for 30 seconds to 1 minute.
Slowly pour in the 1 1/2 cups vegetable broth while stirring to avoid lumps, then add the sliced sun-dried tomatoes and 2 teaspoons tomato paste; stir and bring to a gentle simmer.
Simmer the sauce gently for about 5 minutes to thicken slightly and meld flavors.
Add the 1 cup heavy cream, 1/2 teaspoon Italian herbs, 1/4 teaspoon salt, 1/4 teaspoon black pepper, and the 1 lb gnocchi; stir to combine.
Cover the pan, reduce heat to medium, and cook for 6–7 minutes, stirring once or twice, until the gnocchi are tender and cooked through.
Stir in the 1 cup fresh spinach and 1/2 cup grated Parmesan and cook for about 1 minute until the spinach wilts and the cheese melts into the sauce.
Taste and adjust salt and pepper if needed, then serve topped with fresh basil and extra Parmesan.
