Preheat oven to 350 F.
Toss carrot, parsnip, celery root and squash with shallots, olive oil and thyme and season lightly.
Place in an 8-cup baking dish and roast for 30 to 40 minute, until vegetables are equally tender. Remove thyme sprigs.
Heat 1 tbsp oil and sauté shallot for one minute over medium heat. Whisk in mustard, vinegar and rosemary and reduce heat to low.
Whisk in remaining 6 tbsp oil in a slow drizzle and season to taste.
When ready to serve, toss warm roasted vegetables with warm vinaigrette, garnish with pumpkin seeds and serve.