Place the saucepan on medium to low heat and add some olive oil.
Once it is hot, slowly start adding the flour while constantly stirring.
Do that for about half a minute, then pour in the milk and water while you keep the stirring going.
Add the tomato soup to the pan and season it with a pinch of salt and pepper.
Wait until the soup starts to boil, and then leave it for another minute. You can always adjust the flavor by adding a bit more pepper or salt or maybe opting for some paprika to spice it up more.
Put some fresh basil leaves on top, or grill some cheese with a drizzle of olive oil and serve it on the side.