Preheat your oven to 425 degrees Fahrenheit and line a rimmed baking sheet with parchment paper.
Peel the butternut squash and cut it into half inch cubes. Trim the ends off the Brussels sprouts and slice them in half through the stem. Cut the red onion into wedges about an inch thick, keeping the root end intact. Dice the red bell pepper into pieces roughly the same size as the squash.
Spread the butternut squash, Brussels sprouts, red onion, and bell pepper in a single layer on the prepared baking sheet. Drizzle with 2 tablespoons of the olive oil, then sprinkle with salt and black pepper. Toss everything directly on the pan until evenly coated.
Roast for 30 to 35 minutes, stirring once halfway through, until the vegetables are tender and lightly caramelized at the edges.
While the vegetables roast, bring a large pot of heavily salted water to a boil. Add the rotini pasta and cook according to the package directions until al dente. Reserve about a half cup of the pasta cooking water before draining.
Drain the pasta in a colander and set it aside to cool slightly.
In a small bowl or jar, combine the remaining olive oil, minced garlic, balsamic vinegar, Dijon mustard, maple syrup, and fresh thyme. Whisk or shake vigorously until the marinade is smooth and slightly thickened. Season with a pinch of salt and pepper, then taste and adjust the sweetness or acidity if needed.
As soon as the vegetables come out of the oven, transfer them to a large mixing bowl while they are still hot. Pour about two thirds of the marinade over the warm vegetables and toss gently to coat. Let the vegetables sit for 10 minutes so they can soak up the marinade.
Add the cooked and drained pasta directly into the bowl with the marinated vegetables. Pour in the remaining marinade and toss everything together until the pasta is evenly coated. If the salad looks dry, add a splash of the reserved pasta water, a tablespoon at a time, to loosen it.
Fold in the dried cranberries, crumbled feta cheese, and toasted pecans.
Give the salad one final gentle toss to distribute the cheese and nuts evenly. Sprinkle the chopped fresh parsley over the top just before serving. Serve warm, at room temperature, or chilled, depending on your preference.