Cut one Acorn squash in half and scoop out the seeds. Trim off the stem. Cut the squash into slices along the sections/ribs, then slice each section into 2 or 3 thinner slices.
Clean and trim 1 large or 2 small leeks. Cut the shanks in half lengthwise, then slice them thinly lengthwise into a julienne.
Cut 1 lemon in half and remove the seeds. Cut both halves into quarters, then slice into half rounds.
Toss the leeks, squash and lemon slices (and juice!) with 3 T. olive oil, salt, pepper, and 1 T. fresh rosemary leaves.
Arrange in a cast iron skillet or baking dish so that the squash slices are in a single layer. Cover with foil and bake for 20 minutes.
Remove the foil and continue baking until the vegetables are nicely browned.
Serve atop or alongside spinach and turnip greens sauteed in olive oil with a little garlic.