Start by preparing the dressing so that the flavors have a chance to blend. In a small bowl or a mason jar with a lid, combine the olive oil, balsamic vinegar, Dijon mustard, honey, salt and pepper. Whisk or shake well to combine.
In a large platter, toss sliced peaches, tomatoes, shallots, pistachios, feta and fresh basil. Top with the dressing just before serving.