In a large pot or Dutch oven heat the butter over medium high heat. Add the onions and cook until softened, about 5 minutes. Add the asparagus and cook until slightly darkened, about 3 minutes.
Add the broth and cook until asparagus has softened, about 10 minutes, remove from heat.
Using a blender, food processor or immersion blender, puree until very smooth. Season with salt and pepper. Stir in cream and return to heat, brining to a gentle simmer. Remove from heat, stir in beer.