Method:
Soup
Heat a medium saucepot over medium heat until hot. Add onion and garlic and cook about 4 minutes or until beginning to brown and stick to the pan. Stir in 1/4 cup vegetable broth and thyme and cook 3 to 4 minutes longer or until onions are translucent. Add remaining vegetable broth, tomatoes, tomato paste, and pepper. Bring to a boil over medium-high heat, stirring occasionally. Reduce heat to medium-low and simmer 10 minutes. Remove from heat and use an immersion blender to blend until smooth. (Alternately, allow to cool slightly, and carefully puree in a blender.)
Toasts
In a small bowl, use a fork to mash together avocado, lemon juice, basil and olives, if using. On each toast, spread avocado mixture evenly and garnish with additional basil, if desired. Serve soup with avocado toasts alongside.