Broccoli Cheddar Soup

Why This Broccoli Cheddar Soup Works

As the butter, onions, and garlic cook together, the onions soften and lose their sharp bite. They start to taste a little sweet, which keeps the soup from tasting flat. When the flour goes in, it soaks up the melted butter and coats the onion pieces. After a minute or two, that flour-butter mix changes from pasty to smooth and golden. At this point it can grab onto the broth and milk without turning lumpy.

Once the broth and milk are whisked in and heated, the flour swells and thickens the liquid. The pot goes from thin and watery to creamy and slightly heavy. While the soup simmers, the broccoli sits in that hot liquid and slowly softens all the way through, so it blends into the soup instead of staying crunchy. When the cheddar is stirred in at the end, it melts into the thick base instead of sinking or clumping. The cheese spreads through the whole pot, giving a smooth, cheesy soup that still has tender pieces of broccoli in every spoonful.

Mistakes To Avoid

Letting the flour sit in the butter without stirring or cooking it long enough leaves a raw flour taste and a pasty texture. The roux stays pale and powdery, and when the liquid goes in, the soup can turn grainy instead of smooth and thick.

Pouring all the cold milk and broth in at once can shock the hot roux and make it clump. Instead of dissolving, the flour forms little lumps that never fully break down, so the soup ends up with tiny gummy bits floating in it.

Boiling the soup hard after the milk is added often causes it to scorch on the bottom and form a skin on top. The dairy tightens and separates, so the soup looks curdled and the texture turns slightly gritty instead of creamy.

Adding the cheddar while the soup is bubbling hot makes the cheese seize and split. The fat can float to the top and the cheese forms rubbery strings, so the soup loses that smooth, velvety feel and looks oily.