Melt butter and sweat onions, garlic, shallots until translucent. Add thyme and cardamom. Cover with chicken stock and bring to a boil. Season with salt and pepper. Simmer until tender. Blend really well in a blender. Strain through a chinoise. Adjust seasoning and texture.
For the Balsamic Reduction: In a saucepot over medium-high heat, reduce 1 bottle balsamic vinegar until it's the consistency of syrup.
For the Crostini: Preheat the oven to 300 degrees. Line a baking sheet with parchment paper and brush with extra-virgin olive oil. Season the pan with salt and pepper. Place the bread slices on the baking sheet and season the bread with extra-virgin olive oil, salt and pepper to taste. Sprinkle the bread with grated Parmesan cheese. Transfer the slices to the oven and bake until golden, about 5 minutes.
To serve, heat soup in a separate pot, whisk in whipped cream. Ladle into bowl. Garnish with Balsamic Reduction, shaved Parmesan cheese and Crostini.
This recipe was provided by a chef, restaurant or culinary professional. It has not been tested for home use.