Preheat the oven to 425 °F. Lay out two sheet pans.
In a large bowl, add the gnocchi, broccoli florets, butternut squash, red onion, olive oil, thyme, sea salt, onion powder, and black pepper. Toss to combine until the vegetables and gnocchi are evenly coated in oil and seasoning.
Divide the mixture between the two sheet pans, spreading it out in a single layer for even roasting.
Roast for about 25 minutes, stirring once halfway and switching the position of the pans for even roasting. It's done when the butternut squash is fork-tender.
While the vegetables are roasting, prepare the brown butter sauce. Heat a light-bottomed medium-sized sauce pan over medium heat (no hotter, you don't want to burn the butter, and a light-bottomed pan will help you see the color). Melt the butter. Once the butter is bubbling, add the minced garlic and cook for about a minute, stirring frequently with a wooden spoon.
Add the sliced sage to the butter and continue to stir frequently. Watch the butter carefully (do not walk away!). The brown butter is done once you see the milk solids turning a golden/brown color, and you smell a nutty aroma. Once it's done, carefully pour the brown butter into a heat-safe bowl so that it stops cooking and doesn't burn.
When the gnocchi is done roasting, carefully transfer it all to one sheet pan, then drizzle the sauce over top (you may not need to use all the sauce – adjust to your taste). Toss until the gnocchi mixture is evenly coated, season with additional salt and pepper, if desired, and serve. Store any leftovers in a sealed container in the refrigerator and eat within 4 days.