In a large mixing bowl, combine the finely chopped basil, fresh blueberries, diced peaches, and sliced Persian cucumbers. Gently stir to create a colorful medley.

In a small bowl, whisk together Dijon mustard, honey, fresh lemon juice, and a pinch of kosher salt and freshly ground black pepper until smooth.

While whisking, slowly drizzle in the olive oil until the vinaigrette emulsifies and thickens.

Pour the vinaigrette over the prepared salad ingredients and gently stir to coat evenly.

Sprinkle crumbled feta cheese generously over the top of the salad, taking care not to crush it.

Lightly toss the salad once more to distribute the feta without bruising the fruit.

Transfer to a serving dish or plates and enjoy immediately, optionally garnishing with additional basil leaves.