1. Preheat an oven to 400°F. Cut the squash in half lengthwise, scoop out and discard the seeds and guts. Cut into 1/4- to 1/2-inch-thick crosswise slices.
2. In a large bowl, mash the butter, miso, honey, and chili flakes together to make a paste. Add the squash to the bowl and use your fingers to rub the paste all over the squash slices.
Line 2 baking sheets with parchment paper for easier cleanup, lay the squash on the sheets in a single layer, and sprinkle with the salt. Roast until tender and browned, about 30 minutes. Note: cook them a little longer and they’ll become a bit chip-like in their crispy texture.
Sprinkle with the sesame seeds to serve if you like.