Heat the oven to 400°F. Cut the squash in half lengthwise and scoop out the seeds and pulp and reserve for later. Place the squash halves cut side down on a lightly oiled sheet pan and bake for about 30 minutes or until very soft and tender. Let cool for about 10 minutes before using. Meanwhile, separate the squash seeds from the pulp. Discard the pulp and transfer the seeds to a small baking sheet. Drizzle them with the olive oil and season generously with salt, black pepper, and a pinch of cayenne pepper. Toss to combine, then bake until deep golden brown, 12 to 16 minutes (feel free to bake them in the same oven as the squash). Let cool for at least 10 minutes before using, or keep in an airtight container at room temperature for up to 4 days. Scoop out the flesh of the warm squash and add it to a medium mixing bowl along with the butter and a healthy pinch of salt. The heat from the squash should melt the butter. Mash with a fork until smooth. Use immediately, or cover and refrigerate for up to 3 days. Just before serving, preheat the broiler and position a rack near the top of the oven. Place the bread slices on a large sheet pan and broil for 2 to 4 minutes or until lightly toasted, flipping once halfway through. (If the oven is already occupied, you can also bake these for 5 or so minutes on the bottom rack of the oven or toast them on the stove in a large cast iron skillet.) Spread each slice of bread with 1 to 2 tablespoons of mashed squash (the squash can be used cold, if desired, or gently reheated in the oven or microwave until warm). Top with the roasted squash seeds, pomegranate arils, and crumbled goat cheese as desired. Just before serving, drizzle lightly with pomegranate molasses. Serve immediately.