Cold Zucchini Soup

Cold zucchini soup is the answer to August’s zucchini glut. Two pounds of summer squash simmer with chicken broth and a teaspoon of marjoram until soft, then pass through a food mill or blender into a smooth, pale green purée. The marjoram is the small detail that pulls this out of generic territory; its sweet, slightly oregano-like note is gentler than basil and lets the zucchini’s mild flavor stay center stage.

The classic French move here is the béchamel base. Two tablespoons of butter and flour cook into a roux, hot milk gets whisked in, and the mixture cooks for a full 15 minutes until the raw flour taste disappears. Skipping that 15-minute simmer is the most common mistake; an underdone béchamel tastes pasty and chalky, and chilling the soup makes that flaw worse, not better.

The cream goes in cold, just before serving. Stirring it into hot soup would warm everything back up; adding it at the end keeps the soup ice-cold and silky. Chill at least 3 hours so the flavors meld and the temperature drops to where summer soup should sit.

Kitchen Tips

• Use young, slender zucchini if you can. The big baseball-bat ones from the garden need to be seeded first or the soup gets watery and bitter.
• Don’t skip cooling the butter-flour mixture before whisking in the hot milk. Hot fat plus hot liquid creates lumps; the temperature contrast is what builds a smooth béchamel.
• Taste cold soups warmer than you’d expect when seasoning. Cold dulls flavors, so what tastes nicely salted at room temp will taste flat after chilling. Slightly over-season.
• A swirl of olive oil and a pinch of flaky sea salt over each bowl just before serving brightens the whole thing.

Variations

• Swap chicken broth for vegetable broth to make the soup vegetarian.
• Stir in a tablespoon of fresh chopped dill or chives along with the parsley garnish for a brighter, more herbaceous finish.
• Add a peeled garlic clove and a small shallot to the simmering pot for a more savory base.