Danish Cold Buttermilk Soup with Rhubarb

During the summer time in Denmark we have a very traditional dish which is called Koldskål. Directly translated Koldskål means Cold Bowl which probably does not make much sense. Nevertheless, Koldskål is a super popular summer dish in Denmark. It is probably the second most consumed diary product, after regular milk, during the summer and especially on the very hot summer days it is probably the most consumed dairy product. In Denmark, this refreshing summer dish is mainly sold ready-to-serve in cartons. However, making homemade Koldskål is super easy and does not require any master skill in the kitchen - I will show you how this is done further down this page.

Koldskål
The name Koldskål or Cold Bowl is actually a very clear and describing name for this dish. Koldskål has a very refreshing, sweet and a little sour taste - it is a perfect 'snack' or beverage for a hot summer day if you ask me. During the summer, I personally almost always have a prepared bowl with this buttermilk soup in my fridge. I typically have some late in the evening or sometimes I simply just skip dinner and substitute it with a bowl of Koldskål.

Danish Buttermilk Soup with Rhubarb
The traditional Koldskål is based on a few and simple ingredients where the main ingredients are two different soured dairy products; buttermilk and 3.5% soured milk. Besides the two dairy products, this dish also contains some sugar, egg yolks, vanilla and lemon juice - this is the six ingredients used to make the traditional Danish Buttermilk Soup. If you are looking for this basis and traditional way of making Danish Buttermilk Soup I have a recipe for that here on my blog. The recipe I have listed below is based on the traditional Buttermilk Soup. However, in this version I have added some homemade and super delicious rhubarb sauce. This rhubarb sauce is simply just added and mixed with the buttermilk soup. The rhubarb sauce gives a new and refreshing summer taste to the buttermilk soup - wonderful if you ask me.

Koldskål is typically served with small Danish biscuits called Kammerjunker. However, you can also serve it with fresh strawberries, which is also fantastic.

Instructions
As said above, making a homemade portion of Koldskål or Buttermilk Soup with a twist of rhubarb is actually easy.

Start by cleaning the rhubarb and cutting it into smaller pieces. In a small saucepan heat up the rhubarb, vanilla seeds, sugar, water and lemon juice. Let it simmer/cook for about 15-20 minutes until it is turned into a delicious and thicker rhubarb sauce. Set it aside to cool down while you prepare the buttermilk soup.

In a large bowl, add the sugar, vanilla seeds and egg yolks. The vanilla seeds are scraped out from a fresh vanilla bean. I have a simple guide here on my blog how to do that. Whisk the ingredients into a fluffy mixture. Add the buttermilk and the 3.5% soured milk and whisk again.

When the rhubarb sauce is cooled down, add it to the buttermilk soup and stir to mix. It is that easy to make a Danish Buttermilk Soup with a twist of rhubarb.

Keep the buttermilk soup in the fridge for 2-3 days.

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Danish Buttermilk Soup with Rhubarb

2-3 people
Preparation time: 20 minutes
Total Time: 40 minutes
Danish title: Koldskål med rabarber
Cuisine: Danish
Category: dinner

Ingredients:
Rhubarb Sauce:
250 g (10 oz) rhubarb, diced
0.75 dl (1/3 cup) sugar
0.5 dl (1/5 cup) water
2 tbsp lemon juice
1/2 vanilla bean, the seeds

The Buttermilk Soup:
2 egg yolks
2 tbsp cane sugar (or regular sugar)
1/2 vanilla bean, the seeds
1/2 l (2.5 cups) buttermilk
1/2 l (2.5 cups) soured milk (3.5 % fat)
1 tbsp lemon juice

Instructions:
Rhubarb Sauce:
1. Start by preparing the rhubarb sauce; clean and coarsely dice up the fresh rhubarb.
2. Scrape out the seeds from half a vanilla bean. Mix the seeds with a little sugar - this way you get a better distribution of the seeds in the rhubarb sauce. Do not throw out the empty vanilla bean.
3. In a saucepan; add the prepared rhubarb, vanilla seeds, sugar, water, lemon juice and the empty vanilla bean. Cook everything into a thicker and uniform rhubarb sauce. This typically takes about 15-20 minutes.
4. When the rhubarb is done, remove the empty vanilla bean from the sauce and set the sauce aside to cool off.

Buttermilk Soup:
5. Scrape out the vanilla seeds and mix them with a little sugar. Keep the empty vanilla bean, it still contains much flavor.
6. In a large bowl; add the cane sugar, vanilla seeds and the egg yolks. Whisk everything into a nice and airy mixture.
7. Add the buttermilk and soured milk and whisk to mix.
8. Finally, add the cold rhubarb sauce and stir to mix. Add the empty vanilla bean to the soup - it still has delicious flavor, which will slowly be released into the soup.

If you cover bowl with a lid or similar, you can keep the buttermilk soup in the fridge for about 2-3 days.

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