Mist a large pot with nonstick cooking spray and heat over medium heat. Add the broccoli stems, onions and potatoes and cook, stirring, until softened, 7 to 10 minutes. Add the flour and cook, stirring, until lightly toasted, about 2 minutes. Stir in the broth and bring to a boil. Reduce the heat to maintain a simmer and continue to cook, stirring occasionally, until thickened and the vegetables are tender, 12 to 15 minutes.
Steak broccoli florets and then add rest with rest of it to the soup
