Sauté aromatics: In a medium Dutch oven or soup pot, heat olive oil over medium heat. Add the onion, salt, and black pepper. Cook, stirring occasionally, until softened (about 8-10 minutes).
Layer flavor: Stir in parsley stems, garlic, and red pepper flakes. Cook for 2-3 minutes until fragrant.
Simmer with orzo: Add the homemade vegetable broth and bring to a boil. Stir in the orzo and reduce heat to medium-low. Cook for 8-10 minutes, stirring occasionally, until orzo is tender.
Add greens & beans: Stir in the cannellini beans and seasonal greens. Simmer for 2-3 minutes until greens are wilted and beans are heated through. Remove from heat.
Finish with herbs: Stir in parsley leaves, chives, tarragon, mint (if using), lemon zest, and lemon juice. Adjust seasoning with additional salt and pepper to taste.
Serve: Ladle into bowls and garnish with pecorino Romano if desired. Serve warm and enjoy the healing power of spring in every spoonful.