Preheat oven to 400°F.
Scrub the squash, remove top and bottom, and cut into 1/2” slices. Remove seeds with a spoon.
In a large mixing bowl, toss the squash with olive oil, salt, and pepper to taste. Get in there with your hands and make sure all the slices are coated with oil and seasoning.
Transfer to a foil-lined baking sheet and roast in the oven for 20 - 25 minutes until fork tender.
Flip the slices and rotate baking sheet halfway through to get even browning.
Meanwhile, rinse the sage leaves and dry thoroughly.
Heat butter in a small saucepan over medium heat until the bubble subsides, at this point butter will start to brown.
Immediately add sage leaves to the hot butter and fry for 10-15 seconds until crispy and nutty. Turn off the heat.
Drizzle brown butter with crispy sage leaves all over roasted squash, toss as needed and transfer to a serving platter.