Heat sun-dried tomato oil in a large saucepan over medium-high heat. Add sun-dried tomatoes and onion; cook, stirring occasionally, until the onion is translucent, about 3 minutes. Stir in garlic paste, Italian seasoning and crushed red pepper; cook, stirring constantly, until fragrant, about 1 minute.
Stir in broth; bring to a boil over high heat. Add ravioli; cook, stirring occasionally, until al dente, about 5 minutes. Whisk cornstarch and 1 tablespoon water together in a small bowl; drizzle into the boiling soup. Cook, stirring, until slightly thickened, about 1 minute. Remove from heat.
Add spinach, cream and lemon juice; stir until the spinach is wilted, about 1 minute.
