Line a baking sheet with parchment paper and wash and chop the produce. Set the broccoli and cauliflower aside in a bowl.
Stir the olive oil and melted butter in a small bowl, then toss about half of the mixture with the squash, brussels sprouts, and apples.
Spread the Brussels sprouts, squash, and apples evenly on the baking sheet, season with salt and pepper, and roast for 20 minutes.
While those veggies are roasting, toss the broccoli and cauliflower with the remaining oil-butter mixture and season with salt and pepper.
After 20 minutes, remove the pan from the oven and give everything a toss. Then, add the broccoli and cauliflower, spray with a little olive oil spray, and return to the oven for 15-20 minutes more or until the veggies are golden, tossing halfway.
Cut the veggies into uniform-sized pieces to help avoid some pieces being undercooked while others are overcooked.
Buy pre-cut veggies for quick and easy prep. I buy precut butternut squash, broccoli, and cauliflower. It's a bit more expensive, but a big time-saver.
No piling up the ingredients! Be sure to spread everything in a single layer on the baking sheet, as overlapping can result in uneven cooking.
If you don’t have a large baking sheet, divide everything between two smaller ones so the veggies and apples roast, not steam.