Add stock, passata and oregano. Stir and bring to the boil. Reduce heat and simmer for 10 minutes, covered.
Remove the pan from the heat, using a stick blender, blend the soup until smooth.
Return to the heat add the tortellini. Simmer until the tortellini are tender, about 5-7 minutes.
Add spinach and basil; stir until wilted. Serve
Notes
Variations - To increase the calories in this dish add more olive oil, use a larger packet of tortellini, top with plenty of parmesan cheese and serve with bread with melted cheese or drizzled with extra virgin olive oil.