Finely chop the onion and saute in butter over medium heat until translucent.
100 grams onion, 15 grams butter
Add the wine and bring to a boil for about 1 minute before adding in the broth. Return to a boil.
125 milliliters Riesling, 750 milliliters chicken broth
Whisk together the sour cream and flour and add in the broth-wine mixture. Reduce to medium-low heat and let simmer for 10 minutes, stirring occasionally.
250 grams sour cream, 2 Tablespoons flour
Add the heavy whipping cream and let simmer for an additional 10 minutes.
125 milliliters heavy whipping cream
Using a small cookie cutter in any shape, cut out 12 little bread shapes from the 2 slices of bread. I used a little leaf cutter, but stars or hearts would be cute, too! 2 slices bread
Cook in butter over medium heat until browned, then transfer to a plate covered with paper towel and dust with a thin layer of cinnamon.
25 grams butter, cinnamon
Season the soup with salt and pepper, then puree using an immersion blender.
Stir in the fresh parsley, reserving some for garnish. Right before serving, add another splash of wine, then top with your cinnamon-dusted croutons.
1 Tablespoon chopped parsley