Heat oil in a large skillet over medium heat. Add onions and peppers and season with salt and pepper. Simmer until vegetables are softened, about 30 minutes, stirring often. Add the minced garlic and the tomato paste and cook, stirring often until the tomato paste turns a dark red, about 3 minutes. Measure 3/4 cup soffritto and set aside; reserve skillet. Transfer remaining soffritto to a container and let cool, uncovered. Mixture can be stored in fridge for up to 4 days or freezer for 3 months.
Preheat oven to 375 degrees. Rub bread slices with remaining garlic clove. Place bread on baking sheet. Drizzle lightly with olive oil and sprinkle each slice with 1 Tbsp. parmesan cheese. Toast for 5 minutes or until cheese begins to brown.
Heat 3/4 cup soffritto and beans in same skillet over medium-high heat. Cook until heated through, about 1-2 minutes. Stir in the broth and bring to a boil. Simmer, scraping up brown bits from bottom of skillet, until liquid thickens, about 4 minutes. Add tomatoes. Simmer until tomatoes are tender, 3-4 minutes. Stir in 2 tablespoons parmesan cheese and season with salt and pepper.
Place one slice of bread per bowl and top with some of bean mixture. Garnish each bowl with the remaining 2 tablespoons parmesan cheese and parsley. Drizzle with olive oil if desired.