Preheat oven to 400 degrees F. Line 2 baking sheets with parchment paper

Slice acorn squash in half horizontally and scoop out seeds and pulp. Peel sweet potato and cut into roughly 2-inch cubes. Dice onion and peel and dice carrots to equal sizes. Set aside.

Place acorn squash cut-side up onto one of the baking sheets. Brush the exposed parts of the squash with olive oil and sprinkle with salt and pepper. Bake in oven for 45 minutes.

Add sweet potato cubes to other parchment-lined baking sheet and drizzle with olive oil and generously season with salt and pepper. Mix and add to bottom rack of the oven, roasting for about 25 to 30 minutes, stirring halfway through.