Pre-heat oven to 400 degrees.
Toss cherry red tomatoes in a large bowl with olive oil, salt and thyme. Spread in an even layer on a baking sheet. Roast for twenty minutes or until tomatoes have burst.
Meanwhile, place a large heavy bottomed pot over medium low heat. Add 1 tablespoon of butter. Once melted, add chopped onion. Cook, stirring occasionally, until onion is soft, about 15 min. Add the garlic and cook for another 4 min.
Remove tomatoes from oven. Increase the heat to medium, add the tomatoes plus their juices and one tablespoon ketchup to the pot. Pour in broth, and bring to a simmer. Cook for another 10 minutes with lid on.
Remove the soup from heat. Puree with an immersion blender until smooth. Stir in 1/4 cup cream and black pepper. Top with garnishes of your choice.