Make the coulis:
Have ready a medium bowl of ice water. In a small saucepan, bring 1 quart of water to a boil. Add the basil and blanch for 30 seconds. Remove from the water with a strainer or slotted spoon and plunge into the ice water.
Once it’s cool, squeeze the basil with your hands to remove excess water. Put the basil in a blender or food processor and add the crushed garlic and a pinch of salt. With the machine running, slowly add 1/4 cup of the oil. If the mixture clings to the side of the container, add the remaining 2 Tbs. oil. Purée until smooth, scraping down the sides of the bowl as needed.
Transfer the coulis to a squeeze bottle or a jar.
Make the soup:
Tip:Be sure to purée in small batches and crack the blender lid slightly (or remove the center cap from the lid). Steam can build up once you start blending, and if the lid is on tight or the blender is overfilled, it will spray hot soup all over you and your kitchen. For protection, cover the top with a dishtowel while puréeing.
In a nonreactive 5- to 6-quart Dutch oven, heat the oil over medium-low heat. Add the onion, celery, and red pepper and cook, stirring occasionally, until the vegetables are quite soft, about 10 minutes. Add the broth, tomatoes, thyme, 1/4 tsp. each salt and pepper, and 1 cup water. Bring to a simmer over medium-high heat. Reduce the heat to low, cover, and simmer for 40 minutes.
Discard the thyme sprig. Let cool briefly and then purée the soup in two or three batches in a blender or food processor. Rinse the pot and return the soup to the pot. If it is too thick, add some of the reserved tomato juice.
Reheat if necessary and season to taste with salt and pepper.
Top each serving with a little coulis.
Make Ahead Tips
The coulis can be made 2 or 3 days ahead and stored in the refrigerator. Allow the coulis to come to room temperature before using. This soup stores beautifully and tastes better the second day. You can keep it in the refrigerator as long as you bring it to a boil every two days. Or you can stash it in the freezer for up to three months.
nutrition information (per serving):
Photo: Scott Phillips