Wash the baby spinach thoroughly and spin or pat dry. Core the apple, then thinly slice (about 1/8-inch slices) and immediately toss in a small bowl with the lemon juice to prevent browning.

Slice other vegetables

If using cucumber, slice thinly. Thinly slice the red onion and separate into rings. Roughly chop the toasted walnuts if not pre-chopped.

In a large salad bowl, combine the spinach, sliced apples (drained of excess lemon juice), cucumber, and red onion. Add the dried cranberries and half of the crumbled cheese and walnuts; reserve the rest for finishing the salad.

Dressing

Make the dressing just before serving: in a small jar or bowl, combine the apple cider vinegar, Dijon mustard, honey, lemon juice, salt, and pepper. Whisk until combined.

While whisking continuously, slowly stream in the extra-virgin olive oil until the dressing emulsifies and becomes slightly thickened. Taste and adjust seasoning—add up to 1/4 tsp more salt or a little more honey if you prefer sweeter.

Assemble & Serve

Pour the dressing evenly over the salad (start with about 3/4 of the dressing and reserve some to allow guests to add more). Toss gently but thoroughly so the spinach and apple slices are coated without bruising.

Transfer the salad to a serving platter or leave in the bowl. Sprinkle the remaining crumbled cheese, walnuts, and fresh herbs over the top. Serve immediately with lemon wedges on the side.

If making ahead: keep dressing separate and dress the salad within 30 minutes of serving to prevent wilting and apple browning.