- Melt the butter in a large saucepan over medium heat. 
- Add sliced onions and cook, stirring frequently until onions are soft and translucent. 
- Keep the heat low to avoid browning the onions. 
- Sprinkle flour over the onions, stirring continuously to blend. 
- This step forms a base for the soup's consistency that you'll love! 
- Gradually add the beef broth and bouillon cubes. 
- Stir well and bring the mixture to a gentle simmer while ensuring all flour lumps are dissolved. 
- Reduce the heat to low and stir in the heavy cream. 
- You should avoid boiling the cream to prevent it from curdling. 
- Add the cheddar cheese, stirring constantly until fully melted. 
- Taste the soup and adjust the seasoning with salt and pepper if needed.