Preheat a small dry skillet over medium heat. Add the walnuts and toast, stirring or shaking the pan, until fragrant and lightly browned, about 4–5 minutes. Transfer to a plate to cool and roughly chop once cooled.

Cook bacon

Lay the bacon slices in a cold skillet without overlapping and place over medium heat. Cook, turning occasionally, until crisp and browned, 8–12 minutes depending on thickness. Transfer to a paper towel-lined plate to drain and cool, then crumble or chop into bite-sized pieces.

Prepare fruit & cheese

Wash the plums, halve and pit them, then slice each half into 3–4 wedges depending on size so you have attractive slices for the salad. If using bocconcini, drain and pat dry; if using a larger fresh mozzarella ball, tear into bite-sized pieces.

Make dressing

In a small bowl or jar combine the balsamic vinegar, Dijon mustard, honey, minced garlic, salt and pepper. Whisk to combine, then slowly drizzle in the olive oil while whisking until the dressing is emulsified. Taste and adjust seasoning (add more honey if too sharp, or more vinegar if you prefer tang).

Assemble salad

Place the mixed salad greens in a large bowl or arrange on a serving platter. Scatter torn basil leaves over the greens. Add the sliced plums, torn or sliced mozzarella, toasted walnuts and crumbled bacon evenly over the salad.

Drizzle about two-thirds of the dressing over the salad and gently toss with tongs just until the ingredients are coated—avoid over-tossing to keep the plums and mozzarella intact. Reserve the remaining dressing for anyone who wants extra.

Finish & serve

Taste and adjust: sprinkle the coarse sea salt and a little more freshly ground black pepper over the salad. If using, finish with a light drizzle of balsamic glaze for a sweet-sharp accent. Serve immediately.