Wash and spin-dry the mixed salad greens until mostly dry. If using pear or apple, core and thinly slice (about 1/8-inch slices). Place the greens in a large shallow bowl or platter and arrange fruit slices around or on top of the greens.

Add onion

If using red onion, slice very thinly (use a sharp knife or mandoline) and separate into rings. Scatter the thin onion slices over the greens and fruit.

Add cheeses and walnuts

Tear or halve the mozzarella into bite-size pieces and distribute evenly over the salad. Sprinkle the crumbled blue cheese in small clusters around the salad so every forkful can include some. Scatter the toasted walnuts over the top.

Dressing

Whisk dressing

In a small bowl or jar, combine the white wine vinegar (or sherry vinegar), Dijon mustard, honey (or maple), and fresh lemon juice. Add the salt and black pepper. While whisking continuously, slowly drizzle in the olive oil until the mixture emulsifies and thickens slightly. Taste and adjust seasoning — add a pinch more salt or a touch more honey if needed.

Alternate method

Alternatively, place all dressing ingredients in a lidded jar and shake vigorously until well combined.

Assembly & Finish

Right before serving, drizzle 2 to 3 tablespoons of the dressing over the salad (reserve any extra dressing). Gently toss the salad once or twice to coat the leaves lightly without breaking up the cheeses. Taste and add more dressing if desired.

Sprinkle the coarse sea or flaky salt lightly over the mozzarella pieces to enhance their flavor. Finish with an extra scattering of toasted walnuts if using.

Serve immediately on individual plates or family-style. Pass remaining dressing at the table.