Preparation Scatter bread on a rimmed baking sheet in a single layer. Let stand at room temperature to slightly dry out, about 2 hours. Working in batches, cook collards and kale separately in a large pot of boiling salted water until slightly softened, about 3 minutes per batch. Rinse to cool. Squeeze out excess water; roughly chop. Set aside. Heat 1/4 cup oil in a large heavy pot over medium heat. Add carrots, celery, and leek; stir often until softened, 8-10 minutes. Add garlic and red pepper flakes. Cook, stirring until fragrant, about 1 minute. Add tomatoes, crushing with your hands as you add them. Cook, stirring frequently, until liquid is evaporated and tomatoes begin to stick to the bottom of the pot, 10-15 minutes. Add broth, beans, thyme, marjoram, bay leaf, and reserved greens; season with salt and pepper. Bring to a boil, reduce heat, and simmer until flavors meld and soup thickens slightly, 40-50 minutes. DO AHEAD: Soup can be made 2 days ahead. Let cool slightly; chill until cold. Cover and keep chilled. Reheat before continuing. Store bread airtight at room temperature. Just before serving, gently stir bread and 1/4 cup oil into soup. Divide among bowls, top with Parmesan, and drizzle with oil.
Preparation Scatter bread on a rimmed baking sheet in a single layer. Let stand at room temperature to slightly dry out, about 2 hours. Working in batches, cook collards and kale separately in a large pot of boiling salted water until slightly softened, about 3 minutes per batch. Rinse to cool. Squeeze out excess water; roughly chop. Set aside. Heat 1/4 cup oil in a large heavy pot over medium heat. Add carrots, celery, and leek; stir often until softened, 8-10 minutes. Add garlic and red pepper flakes. Cook, stirring until fragrant, about 1 minute. Add tomatoes, crushing with your hands as you add them. Cook, stirring frequently, until liquid is evaporated and tomatoes begin to stick to the bottom of the pot, 10-15 minutes. Add broth, beans, thyme, marjoram, bay leaf, and reserved greens; season with salt and pepper. Bring to a boil, reduce heat, and simmer until flavors meld and soup thickens slightly, 40-50 minutes. DO AHEAD: Soup can be made 2 days ahead. Let cool slightly; chill until cold. Cover and keep chilled. Reheat before continuing. Store bread airtight at room temperature. Just before serving, gently stir bread and 1/4 cup oil into soup. Divide among bowls, top with Parmesan, and drizzle with oil.