Combine the cannellini beans, tomatoes, red onion, olive oil, balsamic vinegar, basil, garlic, salt, and black pepper. Let the mixture marinate for 20 minutes.
Preheat the oven to 400 degrees F. Arrange 24 baguette slices on a baking sheet and brush them with olive oil.
Sprinkle the baguette slices with Parmesan and bake for 8 to 10 minutes, turning the pan once, until crisp and golden. Let the crostini cool for 5 minutes.
Blend the drained cottage cheese, lemon juice, lemon zest, and salt in a food processor until smooth, thick, and airy.
Spread the whipped cottage cheese generously over the crostini. Spoon the marinated white bean mixture on top, allowing excess liquid to remain in the bowl.
Serve the bruschetta immediately so the Parmesan crostini stay crisp. Finish with additional basil and black pepper if desired.