"This is, by far, my family's favorite soup. It can be served either hot or cold. We love to make huge batches when the zucchini in our garden is in season and then we freeze the extra. Awesome with a loaf of crusty bread for dipping!"
Melt butter in a saucepan over medium heat. Cook and stir onion and green onion in hot butter until softened, about 5 minutes. Add chicken broth, zucchini, vinegar, and dill to the saucepan; bring to a boil. Gradually pour farina into the broth mixture while stirring. Reduce heat to low, loosely cover saucepan, and cook broth mixture at a simmer until the zucchini is tender, about 15 minutes more.
Blend soup with an immersion blender until smooth. Add cream cheese and blend again until the cheese is fully incorporated.