Rinse the watercress thoroughly in cold water to remove grit. Spin in a salad spinner or pat dry with clean kitchen towels until mostly dry — excess water will dilute the dressing.

Prepare pears and onions

Core and thinly slice the pear into 1/8" (3 mm) slices. If using red onion, thinly slice and soak in cold water for 5 minutes to mellow the bite, then drain and pat dry.

Toast walnuts (if not pre-toasted)

Heat a dry skillet over medium heat. Add walnut halves and toast, stirring frequently, until fragrant and lightly browned, 3–4 minutes. Remove to a plate to cool, then roughly chop.

Make dressing

In a small bowl or jar combine the lemon juice, honey, Dijon mustard, and white wine vinegar. Whisk to combine until honey and mustard are incorporated.

Slowly whisk in the olive oil until the dressing emulsifies and thickens slightly. Season with kosher salt and freshly ground black pepper. Taste and adjust — add a little more honey if you prefer sweeter, or more lemon for brightness.

Assemble salad

Place the dried watercress in a large mixing bowl. Add the sliced pear and drained red onion (if using).

Pour about three-quarters of the dressing over the salad (reserve some to serve). Toss gently but thoroughly with clean hands or salad tongs so the leaves are evenly coated without bruising.

Scatter the toasted chopped walnuts over the dressed greens and gently crumble the chèvre on top in even pieces. Add the reserved dressing to taste if needed.

Transfer to a serving platter or divide among 4 plates. Garnish with thinly sliced mint or chives and an extra sprinkling of chèvre if desired. Serve immediately so the watercress remains crisp.