In a heavy pan (I used a dutch oven pan like this one or this one) melt butter and then saute onions until translucent, about 5 mins.
Step two
Add tomato juice, canned tomatoes and half & half, bring to a boil over medium heat, stirring occasionally for 10-15 mins. Add basil, salt and pepper, then continue to boil over a medium low heat until by a 1/3. stirring frequently.
Step three
Puree soup with an immersion blender (click here for the one I used) or in a blender, in batches if you use a normal blender. Salt to taste.
Serve
Garnish with additional basil, a dollop of cream and/or fresh croutons and enjoy!