Bring a medium saucepan to a boil over medium-high heat. Add the shelled fava beans and cook for 1-3 minutes depending on the size of the fava beans. Transfer the cooked fava beans into a bowl with iced water to stop the cooking process. Remove the cap at the top of the fava bean and slip each bean out of its waxy coating.
Heat olive oil in a large saucepan over medium-high heat. Add shallot and ramps and cook for 3 minutes or until fragrant.
Add shelled fava beans and vegetable stock. Cook for 20 minutes.
Transfer soup mixture to high speed blender and puree until smooth.
Scrape puree back into saucepan. Add cream and bring to a simmer for another 5 minutes. Season with salt and freshly ground pepper to taste. Thin soup with 1 tablespoon of water at a time for desirable consistency.
When ready to serve, divide soup among serving bowls, swirl through a dollop of creme fraiche, top with chive blossoms, and freshly ground pepper if desired.