- 2 tablespoons unsalted butter
- 8 white button mushrooms, cut into 1/4-inch slices
- 6 shallots, sliced
- 3 garlic cloves, grated
- 2 bunches kale, stems and center ribs discarded, cut into 1-inch strips, divided
- 1 tablespoon kosher salt
- 1 teaspoon white pepper
- 3 Idaho potatoes, peeled and cut into 1/4-inch-thick slices
- 1 cup heavy cream
- 1 cup whole milk
- 2 bunches watercress, trimmed, plus more for garnish
- 3 tablespoons reduced-fat sour cream (optional)
- 8 slices whole-grain bread (optional)
- In a large pot over medium heat, add butter. As it melts, add mushrooms, shallots, garlic, half the kale, salt and white pepper. Cook until shallots are translucent and kale starts to cook down, 3 to 5 minutes.
- Add potatoes, remaining kale and 2 cups water. Cover; reduce heat to low. Cook until potatoes are tender, 15 to 20 minutes.
- In a medium pot, simmer cream and milk; season with salt and pepper. Add watercress to soup; stir to wilt; remove soup from heat. Stir in cream mixture; simmer.
- In a blender, blend soup in batches until smooth. Divide among 8 bowls; top with sour cream and watercress leaves, if desired. Serve with whole-grain bread, if desired.