Summer Lobster Salad with Tarragon-Lemonade Spritzer

Preparation : Bring large pot of salted water to boil and add potatoes. Cook potatoes until tender when pierced with a fork and drain in a colander. When cool enough to handle, slice potatoes into 1/4" thick rounds and lay onto individual plates. Place lobster, scallions, tomatoes, cucumber, radish, and corn in a medium bowl and toss with lime juice, olive oil, basil leaves, and salt and pepper to taste. Evenly distribute the lobster salad over the potatoes. To make lemonade, place the sugar and tarragon leaves into the bowl of a food processor and pulse until the leaves are crushed to small bits and incorporated well with the sugar. In a large pitcher, combine the infused sugar with the lemon juice and waters and stir well to dissolve sugar. Serve lemonade over ice and garnish glasses with a sprig of tarragon.