Warm olive oil in a soup pot over low heat. Add red onion and a pinch of salt to pot. Cook onions until they become translucent, about 9 minutes. Add chopped garlic to pot and cook for one minute. Pour tomato puree, vegetable stock, and black pepper into pot. Cook for 20 minutes over medium heat, stirring occasionally. Remove pot from heat, and allow to cool slightly. Puree soup with and immersion blender. Taste soup and add additional salt, pepper, and/or sugar to taste. Tear or cut the baguette up into 1 inch cubes, add to soup, then puree soup again breifly so the bread becomes incorporated into the soup.
Serve hot or room temperature with a drizzle of extra virgin olive oil and 2-3 chopped basil leaves on top. (Especially good with basil infused olive oil.)
Other serving suggestions: Along with olive oil and basil, top with sliced pancetta, shredded parmasan cheese, and/or toasted bread that has been rubbed with garlic and cut into small squares.