In a sauté pan over medium heat, melt butter, add shallots, salt and pepper to taste. Watch carefully, you don’t want the shallots to brown.
When shallots are just starting to get translucent, add the flour and blend in.
Add broth, bring to a boil and cook for one minute.
Add the tomatoes, and cream, bring mixture to a boil, cook for one more minute, stirring constantly.
Remove from heat, pour mixture through a strainer into a sauce pan, add the sorrel, mix in and keep warm.