large butternut squash (3 to 4 pounds)
tablespoons extra-virgin olive oil
Kosher salt and black pepper
tablespoons unsalted butter
teaspoon apple cider vinegar, plus more as needed
teaspoon red-pepper flakes, plus more as needed
cup fresh mint leaves (optional)
- Arrange a rack at the bottom of the oven and heat to 425 degrees. Slice the squash 1/2-inch-thick crosswise. (No need to peel.) Cut slices in half, if desired, to make half moons. Remove the seeds from the squash with a spoon and discard.
- On a rimmed baking sheet, toss the squash with the olive oil, and season with salt and pepper. Spread in an even layer and roast on the bottom rack until browned, 20 to 25 minutes. Flip and roast until tender, another 5 to 10 minutes.
- After you flip the squash, make the brown butter: Melt the butter in a small saucepan over medium. Cook, swirling occasionally, until the foam subsides, the milk solids turn golden-brown and it smells nutty, 3 to 4 minutes. Remove from heat and add the vinegar and red-pepper flakes. Season with salt and pepper and set aside on the stovetop until the squash is ready. (The heat from the oven keeps the butter from hardening.)
- Dip a piece of squash into the vinaigrette, try it, and adjust vinegar, salt and red-pepper flakes to taste. Spoon the vinaigrette over the squash and top with mint leaves, if using, and flaky salt.