Necessity -- or is it forgetfulness? or humidity? -- being the mother of invention, this cucumber ribbon salad owes its spectacular ranch-style buttermilk herb dressing to a great pantry, and to my strong desire not to drive five miles to the grocery store for a quart of buttermilk on an unbearably hazy-hot-humid day. Powdered buttermilk, a baking pantry staple that will keep perfectly happy in the refrigerator for months, contributes the characteristic tangy ranch flavor, with a boost from Greek yogurt and a small amount of mayonnaise. I like the combination of dill, parsley and chives from my garden for a vibrant herby punch. The overall result? Delicate, much more so than traditional ranch dressing. I'm planning to use the leftover dressing on grilled salmon. The cucumber salad didn't last much longer than the time it took to photograph it. I ate it for breakfast. All of it.