Preheat your oven to 425°F.
Lay your butternut squash on its side on a cutting board and use your sharpest knife to cut off the top and bottom.
Peel the skin, then slice the squash in half, stem to stem.
Use a sturdy spoon to scrape and scoop out the insides and discard them.
Cut squash into 1-inch cubes, then add to a large sheet pan.
Drizzle with olive oil and season with salt and pepper.
Use your hands to toss the squash so it is evenly coated and arranged in an even layer.
Place in the oven to roast for about 15-20 minutes, or until squash is golden brown and bottoms are caramelized.
During the last few minutes of roasting, brown your butter.
Melt the butter over medium heat in a skillet, stirring occasionally.
Once the butter starts to smell nutty and the foam subsides, use a wooden spoon to scrape up the browned bits from the bottom of the pan.
Add the rosemary, stir, then whisk in the maple syrup.
Add the butternut squash to the browned butter and toss to coat.
Sprinkle with flaky sea salt and more fresh ground black pepper to taste.
