Melt butter (hold back 2 tbsp.) in a large fry pan over medium-high heat. Add the parsnips and squash; stir to coat with butter. Cover and cook until browned, about 5 minutes.
Stir the vegetables and reduce heat to medium-low. Cover and cook, stirring occasionally, until the vegetables are tender, 10-15 minutes more. Add the sage, thyme, maple syrup and the remaining 2 tbsp. butter. Season with salt and pepper and stir to combine.
Transfer to a warm serving bowl and garnish with the parsley. Serve immediately.