Dice the root vegetables fairly evenly, and not too thinly—slices (such as parsnip or daikon radish) should be about ½-inch thick; cut other vegetables into ¾-inch dice.
Combine the cut vegetables with the apple and optional fennel in a large mixing bowl. Add the olive oil, syrup, thyme and basil and stir together.
Transfer the mixture to a lightly oiled large roasting pan (line it with foil first if you’d like). Bake for 25 to 35 minutes, stirring every 10 minutes or so, or until the vegetables are just tender and touched with golden brown.
Remove from the oven and allow to cool to room temperature. Season gently with salt and pepper.
When ready to serve, combine the roasted vegetables with the the greens in a serving container. Drizzle in enough dressing to moisten the salad and toss gently. Scatter the pumpkin seeds over the top and serve.