Chilled aromatic herb soup with tomato and toasted bread

When the heat starts to arrive you only feel like eating light, fresh dishes that help us fight the high temperatures, but without stopping to eat well. For that reason I’m always looking for new ideas. And the day I saw this cold herb soup with tomato and toasted bread I fell head over heels for it.

This is a rather peculiar soup, but that’s exactly what makes dishes like this capture my full attention. The recipe is from the book "Bar Tartine" which I’m totally in love with and I highly recommend it. I’ve made some ingredient changes to adapt the recipe to my possibilities.

The base of our soup

Those of you who know me won’t find the ingredient that forms the base of this cold soup surprising. It’s not the first time I’ve used it and it’s thanks to this book. To make it we will prepare a broth konbu dashi. This broth consists of only three ingredients and the result is absolutely spectacular; water, konbu seaweed and katsuobushi (salted and dried bonito flakes).

You can also make this broth with shiitake (if it’s dried it has more flavor), konbu, katsuobushi or a combination of all of them. In all cases the results will be magnificent. What I do recommend, within your possibilities, is that you make it at home. They sell dehydrated mixes… but there’s no doubt that something made by ourselves that we know what it contains is better.

Katsuobushi what is it?

Also known as hanakatsuo (smaller) or kezurikatsuo (larger and thicker) it’s a food prepared from large tuna or bonito that is dried, fermented and smoked. It can be found in a flake format and packaged in small bags. katsuobushi is the base together with konbu of dashi broth, the base of many soups and sauces, like miso soup or soba sauce.

It possesses umami due to its high content of inosine acid which arises from hydrolysis and chemical reactions from yeasts or extracts of fish or meat. This process can also occur naturally when foods are left to cure.

Adding flavor and color

This cold soup has a really powerful and fascinating flavor thanks to the amount of aromatic herbs we will use. In my case I used basil, cilantro, dill and mint. But you can use any you wish. For example tarragon, lovage, parsley, marjoram... Some of these are used in the original recipe, but I couldn’t find them the day I went looking for them.

To enhance these aromas, we will accompany the soup with a touch of garlic and serrano chile. In addition, we will add potato to give a bit of body to the soup along with a touch of creaminess. Finally we will garnish with tomato, herbs and a bit of toasted bread with Thai oil. A true delight.

La Tourangelle Thai wok oil and Revol porcelain soup bowls

Ingredients (for 2 servings)

For the soup:

• 600gr of konbu dashi broth (recipe below)
• 125gr of potato, peeled
• 15gr of fresh basil, leaves only
• 12gr of fresh dill, stem removed
• 12gr of fresh cilantro, leaves only
• 6gr of mint, leaves only
• 30gr of spring onions
• 1/2 serrano chile, around 2gr
• 1 large clove of garlic
• Salt and black pepper to taste

For the konbu dashi broth:

• 1 liter of water
• 20gr of dried konbu seaweed
• 30gr of katsuobushi

For the garnish:

• Aromatic herbs (cilantro, basil, dill and mint)
• 1 red tomato, good quality
• 1 green tomato
• 1-2 slices of bread
• Thai oil
• 1-2 tablespoons of apple cider vinegar

Preparation

Prepare the dashi broth

1. Clean the konbu seaweed and rehydrate the konbu seaweed in water for 25 minutes.
2. Place the water in a pot medium with the seaweed over medium heat. Leave until it begins to bubble.
3. Remove the seaweed and add the dried bonito flakes. Reduce the heat a bit and leave for about 10 minutes. Skim the surface foam as it appears.
4. Remove from the heat and let rest until the flakes begin to sink.
5. Strain and set aside.
6. The remaining broth can be frozen in airtight containers.

Roast the potatoes

1. Preheat the oven to 180ºC with top and bottom heat.
2. Peel the potatoes and cut into slices. Place them on a tray lined with parchment paper.
3. Drizzle with olive oil, season with salt and pepper to taste and bake for 20 minutes or until tender.
4. Remove from the oven and let cool while preparing the soup.

Prepare the soup

1. Fill a medium pot with water and salt, place over medium-high heat and bring to a boil.
2. Prepare a bowl with very cold water from the fridge, and a couple of ice cubes. Set aside.
3. Once the water comes to a boil, add the aromatic herbs and blanch for 45 seconds. You will notice they take on a bright green color.
4. Remove with a slotted spoon and transfer to the bowl with ice water. Leave for 1 minute, remove with the slotted spoon and set aside on a plate.

Process the ingredients

1. In a food processor add the konbu broth together with the aromatic herbs, the sliced garlic, the chopped spring onions and the chile.
2. Process until you obtain a smooth broth. I recommend doing it in 10-second bursts so as not to overheat the blades and spoil the flavor of the aromatic herbs.
3. Add the roasted potatoes and process again, in batches, until you obtain a smooth texture.
4. Pour the soup into an airtight container and refrigerate until ready to use.

Toast the bread

1. Drizzle 1-2 slices of bread with Thai oil and let sit a couple of minutes so it absorbs well.
2. Place in the toaster or on a griddle and toast until it acquires a golden color, but not burnt.
3. We remove it from the toaster or griddle and let it rest for a couple of minutes before cutting it up.

Serve the soup

1. Divide the soup into individual soup bowls like these from Revol.
2. Garnish the surface with aromatic herbs, slices of green and red tomato and some pieces of toasted bread.
3. Place a tablespoon of apple cider vinegar on the surface, a little freshly ground black pepper and serve immediately.

Revol porcelain soup bowls, Pallarès carbon steel knife and Laura Ashley cotton tablecloth

Notes

• The Konbu Dashi broth we can make at home, as I show in the preparation, or use a dehydrated mix. I leave it to your choice.
• If you have leftover broth it can be frozen in an airtight container.
• If you don’t want to use this type of broth, you can always replace it with a homemade meat or vegetable broth.
• Since we use a small amount of potato, if you don’t plan to bake anything else, here’s another way to cook them. Place a pan over medium heat, add a generous splash of olive oil and arrange the potato slices. Let them brown on both sides. Pour in half a glass of water, season with salt and pepper to taste and cover. Cook for 3-4 minutes or until tender.
• Aromatic herbs can be entirely up to your choice. I used these, but feel free to change them for those you have on hand and like better.
• I used a generous slice of seeded sourdough bread. I recommend using a good quality bread, since the flavor will be much better.
• Thai oil goes great with this soup, but you can also use hazelnut or walnut oil.
• If you make the soup during a very hot period, I recommend chilling the bowls for 30 minutes before serving the soup.
• We can refrigerate this soup in an airtight container for 2 days.

This cold herb soup with tomato and toasted bread will be a perfect option for hot days. We all really like gazpacho, but it’s always good to know more options.

You can prepare it ahead of time ready to serve and assemble it either at lunch or dinner. You can even serve it in small glasses as an appetizer alongside other items. We hope you like it and give it a try!