Preheat the oven to 350 degrees. Roast the beets, wrapped in foil, until done. Let cool. For further instruction on how to roast beets go here. When the beets are cool enough to handle, trim off the ends and peel.

Slice the beets very thin with a sharp knife or on a mandoline slicer (this is the kind I use, available on amazon (affiliate link) but you can find them in Japanese markets and cooking supply stores)

Blanch the corn, cool, and slice the kernels off the cob.

Cut the cucumber into a small dice, about the same size as the corn kernels.

In a small bowl whisk together the champagne (or white wine) vinegar with the olive oil, salt and pepper. Mix in the corn and cucumber.

Lay the sliced beets on the plate and top with the corn and cucumber mixture or layer them as shown in the photos. Garnish with basil chiffonade (cut into fine strips).