In a small saucepan, saute onion in butter until tender. Stir in the flour, salt and pepper until blended; gradually add milk and broth. Bring to a boil; cook and stir until thickened, about 2 minutes.
Add broccoli. Cook and stir until heated through. Remove from the heat; stir in cheese until melted.
Broccoli Cheddar Soup Tips
How do you keep broccoli cheddar soup from curdling?
Curdling in a cream soup usually occurs when the milk or cream is added at too high of a heat. As you incorporate the milk and broth into the cooked onion and flour mixture, keep the heat at medium and stir continuously with a whisk. Once all is mixed in, then proceed to heat to a boil.
Why is my soup grainy?
In addition to curdling, cream soups can become grainy due to the type of cheese used. For best results, don’t use pre-shredded, packaged cheese; shred the cheese directly off a block. Additionally, before adding the cheese, you could add one small peeled and diced russet potato to the soup. Once it has cooked, use an immersion blender to puree the potato as you add the cheese. This will help emulsify the milk and cheese, keeping the soup creamy without affecting flavor.