Preparation Steps

• Make the glaze first: combine balsamic vinegar and honey in a small saucepan and bring just to a simmer over medium heat. Let it bubble gently until reduced by about half and syrupy, 6–8 minutes. Remove from the heat and let cool to room temperature (it will thicken as it cools).
• While the glaze reduces, toast the pistachios in a dry skillet over medium heat, stirring, until fragrant and lightly browned, 2–3 minutes. Transfer to a plate to cool, then chop coarsely.
• In a large bowl, whisk together the olive oil and red wine vinegar. Add the cubed watermelon and gently toss to coat so the fruit picks up the dressing without breaking apart.
• Fold in the thinly sliced red onion, torn basil, and about two-thirds of the crumbled feta. Season with freshly ground black pepper and toss once more. Let the salad sit at room temperature 4–5 minutes to allow the flavors to meld and some juices to form.
• Just before serving, tilt the bowl slightly and use a slotted spoon to transfer portions to plates (this leaves excess liquid behind). Drizzle each portion with the cooled balsamic glaze, then sprinkle the remaining feta and the toasted pistachios over the top.
• Serve immediately for best texture — the watermelon will release more juice if it sits, so wait to dress and glaze until just before eating.