Preheat oven to 375℉.
Wash and pat dry the butternut squash. Lay the squash on its side, slice an inch or two off the bottom and top so the squash can stand up straight. Slice the squash in half and using a spoon remove the seeds and pulp.
Remove the outer layer and root of the onion. Slice into quarters.
Shuck 1 - 2 ears of corn and remove silks.
Peel 5 - 6 garlic cloves.
Place on a large baking sheet in a single layer, onion slices, shucked corn, and pealed whole garlic cloves.
Use a pastry brush to coat everything with a thin layer of olive oil. Note: Make sure garlic cloves are completely coated to avoid burning. Sprinkle salt and pepper over vegetables.
Flip butternut squash flesh-side down on the same baking sheet pan. Roast for 35 to 45 minutes or until squash is tender.
Scoop the flesh of the squash out of its skin with a spoon Note: Be careful, it’s hot.
Transfer to a food processor, flesh of the squash, garlic cloves, ½ cup milk or cream, and 2 cups broth. Blend until smooth.
Cut roasted corn kernels off the cob and stir into the pureed soup. Note: For more spice, add a dash of cayenne, red pepper, or cumin.