Blending beans into tomato soup changes its texture more than its flavor. The result is a fuller spoonful, useful when the tomatoes alone would make a thin bowl.
Soften a chopped onion in oil, add a garlic clove, and stir briefly. Add a 400 g tin of tomatoes, a drained 400 g tin of white beans, and 350 ml vegetable stock. Simmer for about 15 minutes, then blend until as smooth as you prefer.
Use a stick blender carefully in a deep pan, or follow your countertop blender's instructions for hot liquids. Do not seal hot soup inside a blender that is not designed for it. Thin with water if necessary and taste for seasoning after blending.
This makes two generous bowls. Toast is welcome alongside. If the soup tastes dull, try a little salt first; if it tastes heavy, try a small squeeze of lemon. Those are different problems, so add one thing at a time.