Preheat your oven to 400 degrees. Peel, seed, and cube your butternut squash into about 1” pieces. Quarter the onion, apple, and potato. Break open the head of garlic into separate cloves, but don’t peel.
Place veggies on a rimmed baking sheet, toss with olive oil, salt and pepper, then bake for 30 minutes, stirring halfway through.
Once the sheet pan is done baking, carefully scoop the veggies into a stock pot. Be sure and peel the roasted garlic cloves at this point, we don’t want the skins in the soup. Use caution as the garlic will be piping hot.
Add the broth and bring to a simmer. Cover and continue cooking for 45 minutes, stirring once or twice.
Remove the pan from the heat and allow to cool uncovered for 10 minutes before attempting to blend.
I found an immersion blender to be the best tool for the job, also the easiest to clean. But a food processor will definitely do the trick, as will a regular blender, just allow a little extra cooling time, and blend in batches.
Blend until creamy. Top with a spoonful of full fat plain Greek yogurt, croutons, or crispy chickpeas.