Zaansemosterdsoep (Mustard soup) (Dutch)

So far, this is our favorite soup. Hmm or maybe fighting for supremacy with the French onion soup but anyway - the maybe first, maybe second in our soup priority list :). 
Anyway, after tasting this soup no one should be able to say anything bad anymore about the cuisine of Holland, which used to be reputed for being kind of bland. No way. Taste this soup and reconsider :).

After drooling about it for days we finally gathered up the ingredients and time to make it - although, as you'll see, it doesn't require any fancy stuff nor does it take more than half an hour - and were thrilled. It tastes like pure delicate, sour-ish, creamy heaven. 
We recommended you to try it as soon as possible and to serve it with some freshly toasted buttered bread or home dry rustic-style crackers (like dried bruschetta snacks or such), as we did.
Adapted from Crazy mother cooker. 






Ingredients (serves 4):

• 1 medium onion
• 1 liter of good soup stock (can be cube-made or home-made like our vegetable stock or chicken stock)
• 1 tablespoon butter
• 125 g sour cream
• 125 g simple cream cheese (like Philadelphia)
• an optional hot pepper - we didn't used any but replaced with a sprinkle of chili powder
• 2-3 tablespoons of home-style mustard (must have visible ground seeds in it and be slightly sweet)
• 2-3 tablespoons of starch
• freshly ground pepper to taste
• decorating croutons (can be bacon, case in which you need about 10 g - 3 long strips of bacon, like we used, or chopped spring onions - the green parts - case in which you need the leaves from one, if you want to keep it vegetarian)

Peel the onion and finely chop it:

Heat the butter in a medium pot (that will accommodate the rest of ingredients soon).

Fry the onions in it on low heat until they become transparent and slightly golden:

Meanwhile, in small bowl, put the cream cheese, sour cream and mustard:

Mix into an even paste:

When the onions are just starting to brown, add the soup stock (and the chili powder or whole chili pepper) to the pot:

Let it heat until it comes to a boil, then add the cream composition to it:

Leave the whole thing boil on low heat for 2-3 minutes more (not more than that!). At the end pick out the pepper and discard it (if using any). Keep on the heat and quickly add the starch, previously dissolved in 2-3 tablespoons of water. Mix very well and boil for 2-3 minutes more. Allow to cool.
Meanwhile, if using bacon (like us), fry the strips until crispy and then cut them into little pieces:

If using green onions, cut them too into little pieces. Whatever you chose, your croutons are ready. The soup is ready too, after you mixed the starch into it and let it boil for 2-3 minutes more:

Arrange in serving soup bowl, prepare the bread (or crackers, like we used), sprinkle the croutons (bacon or green onions) on top and you're done:

Dig in! :)