Fry the pancetta pieces over medium heat just until slightly browned and cooked through. Remove them to a plate lined with a paper towel to absorb the excess grease.
Wipe out the pan with a paper towel, leaving behind a little bit of fat from the pancetta. Turn the heat to low and add the chopped walnuts, brown sugar, and 1 tablespoon of maple syrup. Toss the nuts in the sugar and syrup until they're well coated and the sugar has begun to dissolve. Continue moving the nuts around the pan over the heat until the sugar mixture becomes sticky and the sugar has completely dissolved. Remove the nuts to a plate lined with baking paper or parchment paper - the nuts will be very sticky while they're hot and the baking paper will prevent them from sticking to the plate while they cool.
Wipe out the pan again with some paper towel and add the olive oil, placing the pan over medium heat. Add the butternut squash cubes and toss them in the oil, seasoning them with some sea salt and pepper.
Let the butternut squash caramelize on one side before turning the cubes to caramelize on the other sides. After you turn them, drizzle 2 tablespoons of maple syrup over the cubes to help with the caramelization and continue turning to brown all the sides. Remove the butternut squash from the pan when the cubes are a little bit soft but not falling apart. You definitely want them to stay together in the pasta salad, and to have a delicious golden caramelization.
Cook the pasta to al dente according to the package directions, making sure to salt the pasta water well. Rinse the pasta under cool water until it reaches room temperature.
Add the pasta to a large bowl, along with the pancetta, the candied walnuts, the butternut squash, the dried cranberries and the baby spinach.
Add the Dijon mustard, the maple syrup, the olive oil, and the balsamic vinegar to a mason jar, along with a pinch or two of sea salt and pepper. Shake these ingredients together well until they're combined and drizzle the dressing over the pasta salad.
Toss everything together well until the salad is completely coated in the dressing and all the salad ingredients are well distributed.
Refrigerate for an hour or two until you're ready to serve, or refrigerate overnight and serve the next day!