Potato and greens soup with Parmesan toast
2 tablespoons extra-virgin olive oil, divided
1 cup finely chopped yellow onion
1 tablespoon minced garlic
1 pound Yukon gold (or other thin-skinned potatoes), cut into 1-inch chunks
4 to 5 cups low-sodium chicken or vegetable broth
1/2 cup dry white wine
6 cups packed torn kale leaves
6 cups packed baby spinach leaves
1 teaspoon red pepper flakes, or to taste
1/4 pound thinly sliced prosciutto
Twelve 1/2-inch-thick diagonally cut slices of baguette
1/2 ounce finely grated Parmigiano-Reggiano cheese
Heat the oven to 400 degrees.
In a large saucepan over medium, heat 1 tablespoon of the oil. Add the onion and cook, stirring occasionally, until softened, about 5 minutes. Add the garlic and cook, stirring for 1 minute. Add the potatoes, 4 cups of the stock and the wine. Bring to a boil, cover the pan and simmer for 10 minutes.
Add the kale, cover the pan, then simmer for another 10 minutes. Add the spinach and the pepper flakes, cover, and simmer for another 5 minutes.
Working in 2 batches, transfer about 3 cups total of the soup solids with a little added broth each time, to a blender and puree until smooth. Be careful, hot foods expand in the blender. Return the puree to the saucepan, add salt to taste and the additional cup of stock if necessary to achieve the desired texture. Heat until hot.
Meanwhile, set a wire rack over a rimmed baking sheet. Arrange the prosciutto slices in a single layer on the rack, then bake on the oven's middle rack for 10 to 12 minutes, or until they begin to crisp. Remove the rack from the sheet pan and set it on the counter to let the prosciutto cool. When cool, crumble the prosciutto.
Arrange the baguette slices in single layer on the sheet pan and brush them with the remaining tablespoon of olive oil. Bake them on the oven's middle shelf until golden brown, 8 to 10 minutes. Sprinkle the grated cheese evenly over them, return the slices to the oven and bake until the cheese is just melted, 1 to 2 minutes.
To serve, ladle the soup into 4 bowls, then top each portion with some of the prosciutto crisps and 3 toast slices on the side.
Start to finish: 1 hour (40 minutes active)
Nutrition information per serving: 630 calories; 120 calories from fat (19 percent of total calories); 13 g fat (3 g saturated; 0 g trans fats); 25 mg cholesterol; 96 g carbohydrate; 8 g fiber; 5 g sugar; 31 g protein; 1,640 mg sodium.