How to Make It
Preheat the oven to 350°. In a large soup pot, melt the butter. Add the onion, carrot, garlic, thyme and coriander and cook the vegetables over moderately high heat, stirring, until softened, about 3 minutes. Add the stock, beans and ham and bring to a boil. Cover partially and cook over moderate heat for 20 minutes.
Meanwhile, toss the baguette cubes with the olive oil and paprika and season with salt. Spread on a baking sheet and bake for about 10 minutes, stirring occasionally, until toasted.
Remove the ham from the soup and cut it into 1/2-inch pieces. Discard the thyme sprigs. Working in 2 batches, transfer the soup to a blender or food processor and puree until smooth. Return the soup to the pot and stir in the diced ham. Season the soup with salt and pepper and ladle into warmed shallow bowls. Top with the croutons and scallion and serve.