Boil potatoes in lightly salted water until fork tender. Drain, cut in half, then place in a bowl. Toast pine nuts in a skillet over low heat until just lightly golden. Remove from heat. Mix together lemon juice, olive oil, mayonnaise, salt & pepper, and pesto until creamy and smooth. Taste and adjust seasonings as you'd like. Pour half the dressing over the potatoes and toss to combine. Add more dressing to taste. Cover and refrigerate the potato salad for a few hours. To serve, sprinkle lots of small basil leaves over the top. Yum!