In large pot, heat buttery oil. Add onion, garlic and salt and cook, stirring often, until beginning to soften, about 5 minutes. Stir in squash. Cook until squash begins to color around edges and soften, about 10 minutes.

In large pot, boil vegetable stock. Add risoni and cook 8 minutes.

To pot with risoni, add squash mixture and stir together until well combined.

Stir in vinegar, parmesan and green onions. Season to taste with black pepper.

Prior to serving, add squeeze of fresh lemon juice and top with green onion.