Preheat the oven to 425 degrees F.
Wash the delicata squash well, scrubbing off any dirt. Cut the squash lengthwise, scoop seeds out with spoon, and slice into thin 1/4 inch pieces (you can toss the seeds, or roast them like pumpkin seeds).
Arrange the pieces on a parchment-lined baking sheet. Drizzle with a little olive oil and season with a little paprika, garlic powder, and salt. Toss well and stick in the oven.
Place the onion (cut into 1/4 inch rounds as well) on another baking sheet. Drizzle with a little oil and salt and stick in the oven as well.
Roast for about 10 minutes, toss them, then continue roasting until the squash has started to turn golden brown (about 25 minutes total).
Meanwhile, mix shallots in small bowl with 3 tablespoons of white balsamic vinegar, 2 tablespoons extra virgin olive oil, 1/2 tablespoon dijon mustard and 1/4 teaspoon of sea salt.
Layer delicata squash onto a plate, topping with the onions. Drizzle the vinaigrette on top, along with the chopped pecans.
Finish with a sprinkle of salt and some cracked pepper.