In a small bowl, whisk the balsamic vinegar, olive oil, and raspberry preserves together until smooth. I like to make sure the preserves fully dissolve so the dressing isn't clumpy. Set it aside while you prep everything else it only takes a minute or two.
Add the chopped walnuts or pecans to a dry skillet over medium heat. Stir them often so they don't burn, letting them toast for about 2-3 minutes until fragrant and lightly golden. Pull them off the heat right away and let them cool slightly before adding to the salad.
In a large salad bowl, add the arugula, the prepared dressing, the toasted walnuts, and the dried cranberries. Toss everything gently so the arugula gets evenly coated without wilting too much. This is the part where the flavors really start coming together.
Layer the thinly sliced pears over the tossed arugula, then scatter the crumbled goat cheese on top. I love fanning the pear slices out for a prettier presentation. Serve immediately so everything stays crisp and fresh.