Preheat oven to 400 degrees. Arrange tomatoes cut side up on a baking sheet lined with foil. Drizzle with 1 tablespoon of olive oil, sprinkle generously with salt and herbs and place in the oven to roast for 35-45 minutes until shriveled. Once the tomatoes are in the oven, slice the top of the garlic off exposing the tops of all of the cloves. Drizzle with a little olive oil then wrap in foil and place in the oven to roast for 35-40 minutes.
I used fresh roma tomatoes for my soup and they were perfect. Larger tomatoes will not lose as much moisture so consider adding less vegetable stock if you're using bigger tomatoes.
To make this recipe with canned tomatoes, used a similar amount of canned tomatoes(approximately 60-70 oz canned tomatoes), drain the tomatoes reserving the liquid for later and spread the drained tomatoes on the baking sheet and proceed with the recipe as directed, adding back the juice from the canned tomatoes instead of vegetable stock or water.
Since roasting the tomatoes and garlic doesn't really add much smokiness I think a dash of liquid smoke would be delicious in this to enhance the roasted flavors!