Wash 1 English cucumber, peel if needed, trim the ends if soft, and slice into thin rounds. Peel ¼ piece purple onion, cut in half, and slice into thin half-rounds. Separate the layers.
Peel 1 piece garlic clove and press, grate, or mash into a paste. Chop the tender green parts of the dill. Squeeze 1 Tablespoon lemon juice and remove any seeds.
In a small bowl, mix ⅓ cup sour cream, lemon juice, garlic, and 1 Tablespoon dill leaves. Season with ½ teaspoon salt (or less) and ⅛ teaspoon black pepper.
In a large bowl, combine cucumber and onion. Add the dressing and stir to coat.
Notes
The basic recipe makes 2 portions as a side dish.
Serve this cucumber salad fresh, right after mixing.
STORAGE: Store leftovers in an airtight container in the refrigerator for up to 1 day. Stir before serving to mix in any released liquid. For best texture, prepare only what you plan to serve. The dressing can be made ahead and stored separately for up to 2 days.